50D Owners Thread - Anything 50D related

I had never used a grip until I had handled Spencers 50D with a grip...

Mine never leaves the camera now...makes it balance out so much better with longer lenses! :)
 
tdodd said:
If you use a tripod and focus with Live AF within Live View then you should get your focus as good as is possible. If switching to Quick AF and focusing again yields softer results then it would appear that AF calibration is the problem, and might be fixed with AF microadjustment. Test with the lens wide open to reduce DOF to the minimum so that focus errors are less easily concealed.

Another possibility might also be stopping down too much. f/8 should be fine, but it would be unusual and perhaps self defeating to stop down more than that as diffraction will start to soften the image at the pixel level. At f/22 the pixels will look like mush. That not a fault of the lens or the camera. That's the problem with examining pixels instead of pictures. Obviously, as you stop down more, shutter speeds reduce, so camera shake or subject movement might also be a problem. If you raise the ISO too high then NR could cause some loss of fine detail and some overall softness.



Then there is the question of camera settings and post processing. Sharpening should be tailored to the needs of each image, its display size and the display medium to be used. One size does not fit all where sharpening or NR is concerned. If you resize (downsize) your images then you should resharpen after downsizing. Personally I prefer to shoot raw and leave decisions on sharpening and NR until later on in my workflow.

There are lots of possible reasons for soft images, but you haven't given us much information to work with.
Click to expand...

Tim,

Many thanks for your reply.
I have been comparing sharpness with the 50d and 10-22, to my previous landscape kit, namely a 10d and Sigma 17-35 . With the 10-22, I have mainly been shooting hand held so far, iso 100 and 200, and between f8 and f13, speed 125 to 200. Using Canon's own DPP software, I have found from my first batch of photo's about 75% appeared on the soft side. I did not experience this with my previous combination.
I have tried my 70-200L on the 50d and find the sharpness equal if not better than when it was on the 10d. I am also finding that the noise with the 70-200 is aceptable at iso 800, but find the 10-22 not aceptable at 400.
Am I correct in thinking you suggest avoiding f22 on the 10-22, even on a tripod ?
Is the 50d more prone to camera shake due to the number of pixels.
As I am keen to avoid softness with the 10-22, is there a sweet spot (f number) for this lens, and would you suggest manaul focus ?

Peter
 
The 50D is not more "prone" to camera shake. It simply makes it more obvious, if there is any, when you pixel peep. The only reason for that is that viewing 50D images at 100% results in a greater enlargment of the image than viewing files from a 40D, 30D, 20D, 10D also at 100%. In the case of the 50D vs the 10D the enlargement is 1.55X greater for the 50D file. Thus shake/blur/diffraction all look 55% worse when pixel peeping. If you can eliminate shake/blur from your shooting (tripod, for example), and avoid stopping down more than necessary, the 50D should pull out more detail when coupled with a sharp and well focused lens.

Avoiding small apertures is not so much about shake (although it might contribute), but about diffraction, which is a limitation of physics, and not a fault with the camera or lens. It's not that you should avoid smaller apertures at all costs, but don't expect sharpness if you pixel peep at 100%. Just like shake, the high resolving power of the sensor makes such aberrations more evident. Viewing the whole image rather than individual pixels should pretty much make such "problems" disappear.

As for sweet spots for the lens, take a look at this review of the 10-22 on a 50D and check out the MTF charts on the second page - http://www.photozone.de/canon-eos/406-canon_1022_3545_50d. You will note that f/5.6-f/8 is probably the sweet spot at most focal lengths, with f/11 showing clear signs of dropping down in sharpness. Beyond f/11...... need I say more?

If you consult a DOF calculator, such as the one here - http://www.dofmaster.com/dofjs.html - you may well see that there is no need to stop down below f/8, or perhaps f/11 at a pinch. The "rules" for APS-C sensors are not always the same as for full frame in terms of DOF and hand held shutter speed guidelines. Furthermore, the typical DOF calculations apply for an image displayed at around 10x8" when viewed from 12" away, not when examined at 100% viewing (which might easily be equivalent to an image 4' across) also from 12" away. Remember as well that DOF is about a zone of acceptable sharpness for a given enlargement and viewing distance. There is only one plane of absolute sharpness, which should be at the focused distance, no more, no less, so be wary of judging the full depth of a landscape image from close by to the horizon and demanding sharpness throughout. It's a physical impossibility.

Finally, depending upon which version of DPP you are using, you may find that viewing files at "Fit to screen" size makes them look softer than viewing at 50% or 100%. This is due to difficulties the resizing algorithm faces when trying to resize to some arbitrary scaling factor instead of exactly 1:2 or 1:1. DPP isn't the only software to have this problem. Lightroom is the same.

I don't know if this will help but here's a sample from my own 50D and 10-22, shot hand held at 10mm, 1/80, f/6.3, 100 ISO. It was shot raw and converted to JPEG in Lightroom with no adjustments.

Full image :
20090428_120749_6259_LR.jpg


Near edge of frame, 100% crop :
20090428_120749_6259_LR.jpg


Far edge of frame, 100% crop :
20090428_120749_6259_LR.jpg


Ignoring the fact that the image itself is pretty pants, I personally cannot grumble about the sharpness. I'm not sure where exactly I focused, but you can bet that it wasn't as close as the near grass, or as far as the tree in the mid distance, never mind the horizon. Apart from the fact that the focus plane can't be in two places at once, there is quite a bit of atmosphere in between the camera and the more distant objects, full of moisture, and diffusing the light coming from those objects. Viewed as a whole the image overall appears sharp. At the end of the day, that is what matters, not the individual pixels.
 
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tdodd said:
The 50D is not more "prone" to camera shake. It simply makes it more obvious, if there is any, when you pixel peep. The only reason for that is that viewing 50D images at 100% results in a greater enlargment of the image than viewing files from a 40D, 30D, 20D, 10D also at 100%. In the case of the 50D vs the 10D the enlargement is 1.55X greater for the 50D file. Thus shake/blur/diffraction all look 55% worse when pixel peeping. If you can eliminate shake/blur from your shooting (tripod, for example), and avoid stopping down more than necessary, the 50D should pull out more detail when coupled with a sharp and well focused lens.

Avoiding small apertures is not so much about shake (although it might contribute), but about diffraction, which is a limitation of physics, and not a fault with the camera or lens. It's not that you should avoid smaller apertures at all costs, but don't expect sharpness if you pixel peep at 100%. Just like shake, the high resolving power of the sensor makes such aberrations more evident. Viewing the whole image rather than individual pixels should pretty much make such "problems" disappear.

As for sweet spots for the lens, take a look at this review of the 10-22 on a 50D and check out the MTF charts on the second page - http://www.photozone.de/canon-eos/406-canon_1022_3545_50d. You will note that f/5.6-f/8 is probably the sweet spot at most focal lengths, with f/11 showing clear signs of dropping down in sharpness. Beyond f/11...... need I say more?

If you consult a DOF calculator, such as the one here - http://www.dofmaster.com/dofjs.html - you may well see that there is no need to stop down below f/8, or perhaps f/11 at a pinch. The "rules" for APS-C sensors are not always the same as for full frame in terms of DOF and hand held shutter speed guidelines. Furthermore, the typical DOF calculations apply for an image displayed at around 10x8" when viewed from 12" away, not when examined at 100% viewing (which might easily be equivalent to an image 4' across) also from 12" away. Remember as well that DOF is about a zone of acceptable sharpness for a given enlargement and viewing distance. There is only one plane of absolute sharpness, which should be at the focused distance, no more, no less, so be wary of judging the full depth of a landscape image from close by to the horizon and demanding sharpness throughout. It's a physical impossibility.

Finally, depending upon which version of DPP you are using, you may find that viewing files at "Fit to screen" size makes them look softer than viewing at 50% or 100%. This is due to difficulties the resizing algorithm faces when trying to resize to some arbitrary scaling factor instead of exactly 1:2 or 1:1. DPP isn't the only software to have this problem. Lightroom is the same.

I don't know if this will help but here's a sample from my own 50D and 10-22, shot hand held at 10mm, 1/80, f/6.3, 100 ISO. It was shot raw and converted to JPEG in Lightroom with no adjustments.

Full image :
20090428_120749_6259_LR.jpg


Near edge of frame, 100% crop :
20090428_120749_6259_LR.jpg


Far edge of frame, 100% crop :
20090428_120749_6259_LR.jpg


Ignoring the fact that the image itself is pretty pants, I personally cannot grumble about the sharpness. I'm not sure where exactly I focused, but you can bet that it wasn't as close as the near grass, or as far as the tree in the mid distance, never mind the horizon. Apart from the fact that the focus plane can't be in two places at once, there is quite a bit of atmosphere in between the camera and the more distant objects, full of moisture, and diffusing the light coming from those objects. Viewed as a whole the image overall appears sharp. At the end of the day, that is what matters, not the individual pixels.
Click to expand...

Tim,

Very informative, with plenty to get me thinking.
I suspect that with newer equipment I am may be guitly of pixel peeping, although before I adjusted the sharpness parameters in camera, I found the images very soft, even after PP.

I think I have been maybe expecting too much sharpness across the DOF and this was the only image I appeared to get close -



This image (ignore the poor composition), appeared on the other hand a bit soft. However I suspect had it been better framed it may have not been as noticeable, as the boats appear sharp, on closer inspection -



Thanks again for taking the time to reply.

Peter
 
I have a question about the maximum burst rate of the 50D, and the point at which faster memory cards won't make any difference.

If my calculations are correct, it fills the buffer at approximately 60mb/s?

So am I right in thinking that any card that writes faster than that is just a waste of money, or is faster always better? Or have I got my maths wrong?
 
The table of data here - http://www.robgalbraith.com/bins/camera_multi_page.asp?cid=6007-9672 - tends to suggest that write rates top out at around 34MB/s, even when used with 45MB/s cards, so I don't know whether a 60MB/s card would yield any practical benefit.

In any case, the 50D produces raw files of ~20MB each and can shoot at 6.3FPS so you're looking at generating data at a rate of more like 120MB/s. The buffer itself can hold up to 16 raw files so you have some room to spare before card speed becomes a major factor. If you keep filling the buffer then maybe a fast card will be an advantage. If you never fill the buffer, or can pause when it does fill, then you might have no need for a fast card at all, unless you are an impatient downloader.
 
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Thanks Tim, as usual, always very helpful!

I'm not too bothered about download times, but I do tend to fill the buffer regularly when doing sport photography as I fire the camera like a machine gun. (wish I'd gone for the 7D and it's 10fps now...)
 
Well sports is an obvious candidate for fast card use, whereas landscapes, macro, portraiture and lots of other things are not. As for the 7D, you can sleep a little easier as it only delivers 8 FPS at best, so not such a massive improvement on the 50D in the speed stakes.

Back to the 50D, if you assume you can clear the buffer at 30MB/s then that should be around 1.5 frames per second, so an 11 second pause ought to see a filled buffer back to empty again. Of course, if you shoot JPEG, and many do for sports, then your buffer capacity will be far larger and your buffer will clear faster too, at least in terms of images per second if not MB.
 
true - but then shooting in JPG just means there's so much less data to play with if the exposure needs correcting.

Well I've got a 30Mb card already, so I guess it's about as good as it's going to get.
 
Just got my 50d (my first dSLR) so will see more of me, with silly questions :)
 
tdodd said:
The table of data here - http://www.robgalbraith.com/bins/camera_multi_page.asp?cid=6007-9672 - tends to suggest that write rates top out at around 34MB/s, even when used with 45MB/s cards, so I don't know whether a 60MB/s card would yield any practical benefit.

In any case, the 50D produces raw files of ~20MB each and can shoot at 6.3FPS so you're looking at generating data at a rate of more like 120MB/s. The buffer itself can hold up to 16 raw files so you have some room to spare before card speed becomes a major factor. If you keep filling the buffer then maybe a fast card will be an advantage. If you never fill the buffer, or can pause when it does fill, then you might have no need for a fast card at all, unless you are an impacient downloader.
Click to expand...

tim your knowledge about cameras is unreal, i couldnt remember half the stuff youve just said in previous posts if i read it 10 times!! :lol:

although i find it very interesting, also ive just switched from srgb to adobe in the colour settings, is this a good choice as ive heard srgb is a very old 'thing'??
also can you change the sharpness in the camera settings? if so how do i do it and how how much should it be changed by on adverage?

and what is pixel peeping?? :thinking:
 
LizardMan said:
I have a question about the maximum burst rate of the 50D, and the point at which faster memory cards won't make any difference.

If my calculations are correct, it fills the buffer at approximately 60mb/s?

So am I right in thinking that any card that writes faster than that is just a waste of money, or is faster always better? Or have I got my maths wrong?
Click to expand...


Lexar have an excellent video on the merits for the new 600X UDMA CF cards



LizardMan said:
(wish I'd gone for the 7D and it's 10fps now...)
Click to expand...

8fps on a 7D , you'll need a 1D to get that 10fps
 
I am a 50d user. I have just read every post in this thread. I have been struggling with noise at even 400 iso. Ok I am partially guilty of pixel peeping but honestly it's been really bad. I just accepted the situation as I was told that the 50d does not deal at all well with nose at high iso.

However, after looking at ct's iso 800 pictures I am really shocked at how noise free they are! I am now pretty sure I am doing something wrong - perhaps underexposing? I will try ettr... At least I now have more hope that I can do something about the noise. The other day I even experienced noise at iso 100 on the dark parts of the image!
 
westley byford said:
tim your knowledge about cameras is unreal, i couldnt remember half the stuff youve just said in previous posts if i read it 10 times!! :lol:

although i find it very interesting, also ive just switched from srgb to adobe in the colour settings, is this a good choice as ive heard srgb is a very old 'thing'??
also can you change the sharpness in the camera settings? if so how do i do it and how how much should it be changed by on adverage?

and what is pixel peeping?? :thinking:
Click to expand...

sRGB and Adobe RGB are two types of "colour space" which define (limit) the spectrum of colours that can be contained within a file. Adobe RGB can store more colours than sRGB but since a file itself is made up of a finite number of bits the difference between colours are further apart, or less finely graduated, in an Adobe RGB file. sRGB is the standard for displaying images on the web and it is also the standard required for most consumer based printing services such as you might find at your local chemist or supermarket.

If you shoot raw then your choice of colour space makes no difference to the raw data itself. The choice between Adobe RGB or sRGB only matters further down the image processing chain when you convert your raw data to an actual image. The problem, if you start out following the Adobe RGB path, but then convert to sRGB at some point later in the image processing chain, you will have wasted data bits describing colours that can not be displayed in your final image.

The bottom line - it is far better to use sRGB for your chosen default, and stick with sRGB throughout your workflow. Only use Adobe RGB if you have avery good reason to be using it, and expect your final output to be created in the Adobe RGB colour space. For the vast majority of us sRGB is the much better choice. It avoids complications and can actually give a better final result.


You can increase in camera sharpening, by adjusting the parameters applied to each of the picture styles. However, those changes will only have an effect when shooting to JPEG or using DPP to process raw files. If you shoot raw and use something other than DPP, such as Lightroom or Photoshop/ACR, then the in camera sharpening parameters will have no effect at all.


Pixel peeping is the term used when you view an image on screen at 100% (or more) so that you can study (and complain about) every single pixel rather than looking at (and enjoying) the picture as a whole. Pixel peeping is what gives cameras a bad name for noise and cameras and lenses a bad name for focus and softness. As often as not the photographer is as much to blame for these problems as the equipment. Pixel peeping has its place, and I am certainly guilty of it, but at least I understand what I am looking at and what it is reasonable to expect when looking that closely at a file.
 
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dubcat said:
I am a 50d user. I have just read every post in this thread. I have been struggling with noise at even 400 iso. Ok I am partially guilty of pixel peeping but honestly it's been really bad. I just accepted the situation as I was told that the 50d does not deal at all well with nose at high iso.

However, after looking at ct's iso 800 pictures I am really shocked at how noise free they are! I am now pretty sure I am doing something wrong - perhaps underexposing? I will try ettr... At least I now have more hope that I can do something about the noise. The other day I even experienced noise at iso 100 on the dark parts of the image!
Click to expand...

Exposure is an important part of the equation, but so is sympathetic processing and also avoiding the temptation to crop too hard, especially when you are shooting at higher ISOs.

Quite simply, the image you get is from the light you capture. Pretty bleedin' obvious, I know, but it's that fundamental. The higher the ISO you use the less light (photons) the sensor is receiving. If you then start cropping you are then throwing away even more light. Remember as well that a camera like the 50D is using a cropped sensor, which already captures far less light than full frame - less than half as much. The higher your ISO and the more you crop the worse your IQ will become.

In the good old days of film you would probably not be cropping at all. You would have a full frame image of 36x24mm (about 1.5x1") and you might print, typically, at no more than 12x8", often less. That's an enlargement factor of just 8X. For a 6x4" print that's an enlargement of just 4X. At most you would probably shoot with film rated at 400 ISO.

Nowadays people are shooting images to a sensor of only 23x15mm, often at ISOs vastly higher than 400, and then enlarging the tiny little images to 100% on screen, thus creating a virtual image of somewhere around 48" wide. That's an enlargement factor of around 50X, which is considerably more than the typical enlargement people would apply to film. Is it any wonder that imperfections may appear when you view at 100%? They're not all down to the equipment either. The photographer needs to do a better job too, if enlarging images by a factor of 50X or so. Blur, shake, misfocus, insufficient DOF, noise (of course), poor lens IQ, poor sensor IQ and poor post processing will all be more easily revealed if you insist on pixel peeping. Get used to it.

Quite honestly, if you can get an image that looks good when fitted to screen (without cropping) then you've done a good job. If it looks good at 100% then you've done an outstanding job, but don't be disappointed if the 100% view is imperfect. It need not come as a surprise in real world shooting in less than optimum shooting conditions.

I'm sure CT will speak up for himself, but my understanding of his workflow is that he converts his raw files with DPP, which does apply some NR by default (whether he says it does or not) and then he performs selective editing to treat the subject and background separately as far as sharpening is concerned. I also suspect that, in the main, CT does not crop his image heavily, because (a) he has the glass to get him a larger image to begin with; (b) he has the skill and experience to know that the best results come from filling the frame rather than cropping the image to within half an inch of its life, and makes the effort to get close to his subject rather than firing off shots in desparation from distances which are simply too far away for good results.

Personally, I use Lightroom exclusively for my editing and I find that I can achieve useful gains in decreasing noise by careful adjustment of my sharpening parameters. There is no point sharpening noise, but by default Lightroom will sharpen noise along with everything else. Increasing the sharpening mask can help quite a bit. Dialing up the luminance NR can help further. Resizing to something of 50% or less should hopefully seal the deal.

Here's a very crude rule of thumb that seems to work out reasonably well when shooting with cameras with high pixel densities like the 50D and 7D....

- At 100 ISO you are collecting as much light as you can. You can, with care, use your files at 100% if you have the need.
- At 400 ISO you are only collecting 1/4 the light and to maintain an equivalent level of IQ you should reduce the area of your displayed image to 1/4, by viewing at 50%.
- At 1600 ISO you are only collecting 1/16 the light and to maintain an equivalent level of IQ you should reduce the area of your displayed image to 1/16, by viewing at 25%.
- At 6400 ISO you are only collecting 1/64 the light and to maintain an equivalent level of IQ you should reduce the area of your displayed image to 1/64, by viewing at 12.5%.

You can apply similar scaling for 200 ISO, to view at 67%, or 800 ISO, to view at 33%. or 3200 ISO to view at 17%.

In this regard light is just like paint. The less of it you have the less area you can cover with equal density. In order to get a good finish (good IQ) you need to concentrate the paint/light into a smaller area, not spread it so thinly that you can see through it to the surface/noise below. In practice it's not quite as simple as that, but as a rule of thumb it is not a million miles from the truth and is a good yardstick for managing expectations. Of course, software manipulation can yield results which beat the rule of thumb as the ISO increases.
 
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Tim

Thanks for the explanation. It does add to my understanding but my concern was more around the relative difference between what ct was getting and what I am getting. I understand that there will be noise. He just gets so much less of it than me and we are using the same sensor. To be clear, I am not cropping. I am filing the frame. I understand that my blurring issues are due to poor technique but they don't contribute to the flecks of noise I am getting all too often.

I read that dpp nr is better than light rooms. However, I don't think i could give up on the convenience that light room brings. I guess I will just have to make do. When I use noise reduction in light room i find i have to really be aggressive to notice any effect and then it softens in the image.

I was really inspired by the results ct achieved. However i have a sinking feeling they beyond me... :(
 
Amir, can you upload a raw file somewhere that I can take a look at and perhaps process through Lightroom for you and see whether I can offer any suggestions. I did a similar thing yesterday for somebody, in relation to his 7D, and I think he found my ideas helpful.

I do hope you're not using HTP or intermediate ISOs, especially those 1/3 stop above the full stop ISOs. HTP = 1 stop underexposure. Intermediate ISOs such as 250, 500, 1000 are 1/3 stop underexposures, but other than the noise you may not realise that the camera is screwing things up for you. If you are actually underexposing on top of that then you will create a "perfect storm" as far as noise is concerned. You might well be underexposed by 2 stops or more, possibly without realising it.

FWIW I never use HTP and I never use intermediate ISOs. I also never use Auto ISO because (even if I thought it was a useful feature) it is as likely as not to choose an intermediate ISO and I absolutely do not want that to happen. I prefer to fix my ISO manually at 100, 200, 400, 800, 1600 etc..

Here is a 100% view of one of my 50D files at 800 ISO, displayed in Lightroom with no edits at all. I find the noise levels here to be completely reasonable, and with some finessing of sharpening (and NR if necessary) I'm sure I could end up with an image that looked just fine when viewed at normal sizes of enlargement....

20100602_094210_.JPG


Here's the resulting image, with no edits applied....

20090706_130958_9277_LR.jpg


Any pereceived noise in the background is not noise at all, not when the file is resized to 17% to get from 4752 pixels wide to 800.
 
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Tim

First of all, the level of noise in your photo is much less than i experience. I only mention this so you know that my expectations are realistic.

HTP and ALO are both disabled.

I have been using auto iso over the last week or two but I had noise issues before this too. I don't understand why intermediate iso's would cause issues. I will research this further. In general I only use 100, 400 and 800. I would like to use auto iso as I quite like it but I will stop if you think that is partly to blame.

I really appreciate your offer of help. Before I take you up on it I'm going to make the following changes to my technique and see what benefits they yield. After that I would like to get you the raw file and see what you think.

  • Start to use ettr
  • Stop focus and recomposing, use a nearer focus point instead (I have now configured joystick to select focus point)
  • Use only full stop iso
  • Use faster shutter speeds even if it means using higher iso (I've been So worried about noise I think I've been getting blur due to slow shutter speedsive been using to compensate for the lower iso)
  • Learn to focus with af-on

I read that blurry images can focus the eye on to the noise hence the moves to eliminate blur.

Does the above sound sensible?
Amir
 
Amir, most Canon cameras do not have a "real" ISO amplification at the intermediate levels. To get 250 ISO, for example, the camera actually takes the shot at 200 ISO. That is your true exposure. Then, internally, the camera brightens the pixel values to simulate shooting at 250 ISO. This is no better than underexposing the shot at 200 ISO yourself and then brightening the image in your own software.

If you end up with an exposure that "looks" correct at 250 ISO then what you've actually done is to underexpose by 1/3 stop and then have the camera brighten the image for you. If you shoot straight to JPEG there may be some small advantage to having the camera do that for you, but if you shoot to raw it is utterly pointless. In fact, you may even find that the little 1/3 stop boost in camera might cause highlights to clip where the original raw capture was actually unclipped.

ALO has no effect on raw files, unless you use DPP to process them, but it can mask a whole myriad of exposure sins, leaving you uncertain as to what the shot really looked like before ALO fiddled with it. ALO is very bad if you are trying to learn to do things properly and it's very bad if you are wishing to take full control of your exposures yourself. For JPEG shooters it may be useful. For raw shooters it is pretty much irrelevant. I leave it turned off because I don't want my preview image and histogram on the back of the camera effed about with my the camera, because it could produce a very misleading interpretation of reality.

The reason noise often looks worse in soft or OOF areas is because the noise is the only thing that is sharp, and contrasty in those areas, and so it sticks out like a sore thumb. In areas with lots of texture and detail the noise is much harder to see. This is partly why it can be advantageous to process the OOF background separately from your main subject. You don't want to sharpen the background at all, probably the opposite, and you probably won't mind hitting it hard with some NR to assist in increasing the smoothness of its appearance. Conversely, for the subject you want to use sharpening to increase perceived detail and to go cautiously with the NR so that you don't lose too much valuable detail.

Probably the very best result you see on the web, especially with high ISO images, comes not only from careful attention at the time of capture, but also careful attention when processing the files too.

As for trading off shutter speed vs ISO, it's all a fine balancing act, and what you need and what you can get away with depends very much on skill/technique, the subject and light itself, and how much you expect to enlarge your image. Displaying uncropped images at 800x533 on the web requires nothing like the care, skill and perhaps a little luck that you will need for viewing at 100%. Blur, shake and noise that might look horrific at 100% can pretty much vanish when you squeeze everything down for web use. e.g. if you have a blur covering three pixels when viewing at 100% you will surely see it. But downsize to 1/6 and that same blur will be only 1/2 pixel wide, and pretty hard to notice.
 
Tim interesting Info at this thread

http://forums.canonphotogroup.com/showthread.php?p=5225

*where they actually suggest a specific order of iso for reducing noise. *It is not at each f stop and the lowest noise iso is 160. I wonder if this applies to 50d too... The thread talks about 40d.

The iso ranking for noise is

ISO 160
ISO 100
ISO 200
ISO 320
ISO 125
ISO 250j
ISO 400
ISO 640
ISO 500
ISO 800
ISO 1000
ISO 1250
ISO 1600
ISO 3200
 
Can someone explain what HTP and ALO are and what effect they have on the image? I also have a 50D but am still a bit of a beginner. Should these be turned off in camera? I have no idea what either of these are!:thinking:
 
dubcat said:
Tim

Thanks for the explanation. It does add to my understanding but my concern was more around the relative difference between what ct was getting and what I am getting. I understand that there will be noise. He just gets so much less of it than me and we are using the same sensor. To be clear, I am not cropping. I am filing the frame. I understand that my blurring issues are due to poor technique but they don't contribute to the flecks of noise I am getting all too often.

I read that dpp nr is better than light rooms. However, I don't think i could give up on the convenience that light room brings. I guess I will just have to make do. When I use noise reduction in light room i find i have to really be aggressive to notice any effect and then it softens in the image.

I was really inspired by the results ct achieved. However i have a sinking feeling they beyond me... :(
Click to expand...


Noooo!!! Amir - good results are not beyond you at all - I feel your frustration mate, but photography and processing go hand in hand- they always have. You'll get there mate, but it's not a horse race. ;) The 50D is a very capable camera - certainly up to 800 ISO in good light.

I agree pretty much with everything that Tim told you earlier - I try to fill the frame as much as possible wherever I can when taking the shot, as the more you crop at the editing stage, the more you make the noise visible, and any subsequent sharpening sharpens not only the subject but that noise too.

Where I'm cropping heavily and therefore getting more noise than I'd like - I first of all select just the bg and then invert the image to sharpen the subject selectively. (No point in sharpening bg noise too).

It's great that I've inspired you Amir - you don't know how pleased that makes me - but don't get disheartened - I've invested in some pretty expensive kit to get me close to the birds and it's still a struiggle to fill that viewfinder frame most of the time. :)
 
dubcat said:
Tim interesting Info at this thread

http://forums.canonphotogroup.com/showthread.php?p=5225

*where they actually suggest a specific order of iso for reducing noise. *It is not at each f stop and the lowest noise iso is 160. I wonder if this applies to 50d too... The thread talks about 40d.
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I don't think you can necessarily assume that what applies for the 40D applies exactly equally to the 50D. It might. It might not. But the general principle that I am especially keen to note is that the ISOs 1/3 stop above the main ISOs are always disproportionately noisy, because they are underexposures that are pushed in camera. Once you get beyond 1600 ISO then I think the rules changes, because for many cameras (not the latest and greatest), such as the 40D for example, their highest true ISO tops out at 1600 and anything above that is a push in camera. I'm not sure about the 50D. I've read that 1600 ISO is also its true top ISO and anything above that is faked but you'll need to look elsewhere for confirmation of the facts.

The ISOs 1/3 stop below the next main ISO above may well appear extra clean, because they are overexposures (with the possible exception of 160 ISO) which are then pulled down in camera, thus reducing noise. As far as noise is concerned they may well be preferable. Howver, the danger with those is that the camera is overexposing internally, before you get to see the image, which might cause highlights to blow before the camera then pulls the pixel values back down to the equivalent of the lower ISO.

160 ISO is a special case, because as I understand it that is believed to be the true native ISO of the 40D, and anything other than 160 has been fiddled around with either in analogue amplification or digital pulling and pushing. The thing is, at ISOs as low as 100, 160, 200 I would argue that the noise is sufficiently unobjectionable as to be a non issue. For that reason I tend to ignore 160 ISO and go for the very acceptable 200 ISO so that my ISO dial is more conveniently limited to only the full stop ISOs.

The native ISO for other cameras like the 50D, 7D, 5D2, 1D3 might be different from 160, but sticking to 100, 200, 400, 800 etc. keeps things simpler (for me) all round and certianly prevents me picking one of the ugly ducklings by mistake.

Of course, one might argue that worrying about 1/3 stop is a bit anal, and perhaps it is, but if you are seeking the cleanest files possible then every little helps.
 
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wippers said:
Can someone explain what HTP and ALO are and what effect they have on the image? I also have a 50D but am still a bit of a beginner. Should these be turned off in camera? I have no idea what either of these are!:thinking:
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HTP is designed to protect your highlight details, and to emphasise details in the highlight range. It does this by deliberately underexposing the image and then applying a special tone curve to brighten up the shadow areas and mid tones without affecting the highlights so much. As a result you may well see more noise in the darker regions. This is why when shooting with HTP enabled you cannot choose to shoot at 100 ISO. The camera is saving 100 ISO for itself and secretly shooting at 100 ISO when you select 2oo ISO. This is also why you can't use 3200 ISO with HTP either. Since 3200 ISO is a fake push from 1600 ISO, by shooting at 3200 ISO with HTP (which means shooting at 1600 ISO in reality) you would be back to square one. It therefore only makes sense to allow HTP to be used at ISOs up to 16oo (real ISO) so that the camera can truly underexpose by 1 stop at a real 800 ISO.

When you shoot to JPEG then HTP may prove advantageous, especially if you want to get good results dtraight from camera without further processing. However, when you shoot to raw, all this HTP shenanigins is a bit of a farce. Nobody should be seeking to underexpose their raw captures. either the exposures should be correct or deliberately exposed to the right. Turning on HTP when shooting raw is, IMO, utterly pointless.

As for ALO, it is a sort of autolevels feature that will mess around with your photo, attempting to improve on the exposure you just made. Maybe it will do a decent job and improve the image. Maybe it will cover up some sort of exposure disaster. Sometimes it may do things you would really prefer it not to have done, but if you shoot to JPEG you won't know until it's too late. If you are trying to learn to become more skilled at setting your exposure then ALO will most likely conceal any errors, at least to a degree, making it very hard for you to understand what went wrong and what went right.

If you shoot to raw then HTP is something you can turn on and off, or adjust, if you use DPP to process the raw files. If you use some other raw converter then whatever your ALO settings in camera, they will be ignored.

A further problem with ALO is that even if you shoot raw, it will be applied to the preview image within the camera, and that in turn will influence the shape of the histogram. In other words you will be left with little clue as to what your captured image - the raw version of it - really looks like. If you are trying to pinpoint your exposure accurately from the histogram, when using ALO, then good luck with that.

These are all features that can help the unskilled or inexperienced to get results which on the face of it may appear to be better than without. For snapshot type shooting they may be a positive blessing. For those trying to learn they are probably an impediment to improvement. For those of us seeking to perfect our capture techniques, things like HTP and ALO are annoyances that will almost certainly undermine our efforts.
 
Ct thanks for the encouragement. I'll stick at it.

Tim ok I'm going to stick to the main iso stops too... I'll never remember those other ones anyway :)

The more I read the more I realize my issue is poor exposure. More specifically i had a habit of underexposing until that TP meet during which hash cake advised me to expose to the right. Now I've read the article I understand the reasoning for doing so.

Thanks again for the tips. This entire thread has been helpful.
 
tdodd said:
HTP is designed to protect your highlight details, and to emphasise details in the highlight range. It does this by deliberately underexposing the image and then applying a special tone curve to brighten up the shadow areas and mid tones without affecting the highlights so much. As a result you may well see more noise in the darker regions. This is why when shooting with HTP enabled you cannot choose to shoot at 100 ISO. The camera is saving 100 ISO for itself and secretly shooting at 100 ISO when you select 2oo ISO. This is also why you can't use 3200 ISO with HTP either. Since 3200 ISO is a fake push from 1600 ISO, by shooting at 3200 ISO with HTP (which means shooting at 1600 ISO in reality) you would be back to square one. It therefore only makes sense to allow HTP to be used at ISOs up to 16oo (real ISO) so that the camera can truly underexpose by 1 stop at a real 800 ISO.

When you shoot to JPEG then HTP may prove advantageous, especially if you want to get good results dtraight from camera without further processing. However, when you shoot to raw, all this HTP shenanigins is a bit of a farce. Nobody should be seeking to underexpose their raw captures. either the exposures should be correct or deliberately exposed to the right. Turning on HTP when shooting raw is, IMO, utterly pointless.

As for ALO, it is a sort of autolevels feature that will mess around with your photo, attempting to improve on the exposure you just made. Maybe it will do a decent job and improve the image. Maybe it will cover up some sort of exposure disaster. Sometimes it may do things you would really prefer it not to have done, but if you shoot to JPEG you won't know until it's too late. If you are trying to learn to become more skilled at setting your exposure then ALO will most likely conceal any errors, at least to a degree, making it very hard for you to understand what went wrong and what went right.

If you shoot to raw then HTP is something you can turn on and off, or adjust, if you use DPP to process the raw files. If you use some other raw converter then whatever your ALO settings in camera, they will be ignored.

A further problem with ALO is that even if you shoot raw, it will be applied to the preview image within the camera, and that in turn will influence the shape of the histogram. In other words you will be left with little clue as to what your captured image - the raw version of it - really looks like. If you are trying to pinpoint your exposure accurately from the histogram, when using ALO, then good luck with that.

These are all features that can help the unskilled or inexperienced to get results which on the face of it may appear to be better than without. For snapshot type shooting they may be a positive blessing. For those trying to learn they are probably an impediment to improvement. For those of us seeking to perfect our capture techniques, things like HTP and ALO are annoyances that will almost certainly undermine our efforts.
Click to expand...

Cheers for the info Tim. Very helpful (as are all your inputs into this thread so far!) :thumbs::thumbs:
I'd like to learn to get the correct image by technique rather than relying on a digital program to possibly hide my errors, so I'll be turning them both off I think. I assume the setting are in camera under the Custom Settings menu?
 
Note to moderators: Can we have a forum tool which allows us to subscribe specifically to tdodd's erudite postings? :lol:
 
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I'd like to know how he finds time to actually take any pictures? With all the reading up on stuff, reading and replying in depth to forum posts...
 
Nifkin said:
Note to moderators: Can we have a forum tool which allows us to subscribe specifically to tdodd's erudite postings? :lol:
Click to expand...

I know, he does tend to go on a bit.:D

But without his expertise a lot of us, including me would still be guessing.
 
I saw a 1D MkIV in a shop yesterday, in a single glass box on its own.

I got the distinct impression that if anyone came within a metre of it, sirens would go off, dogs would be released, poison darts would be fired from the walls, and you'd end up running down a corridor with a boulder hot on your heels.
 
another question for tim :D

ive noticed in my settings that i have mirror lock up, iso noise reduction settings etc, ive never touched these as i dont know what they do, have you or any other had experience with changing these settings? :)
 
westley byford said:
another question for tim :D

ive noticed in my settings that i have mirror lock up, iso noise reduction settings etc, ive never touched these as i dont know what they do, have you or any other had experience with changing these settings? :)
Click to expand...

Mirrot lock -up is to reduce the risk of camera shake due to mirror slap, usually used for long exposures. The camera would be on a tripod. If you enable mirror lock up in the menu, the first press of the shutter button (or remote release) raises the mirror (pause for any vibration to die away) - the second press fires the shutter. MLU stays set until you clear it in the menu.

I usually keep in-camera noise reduction either OFF or on the minimum setting. It reduces noise in your shots, in various strengths depending on the setting, but like all NR it can have an adverse effect on fine image detail, so I prefer to deal with NR in post processing if necessary.
 
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Just to add to what CT said....

With mirror lockup, if the timing of your shots is not critical, and you don't have a remote release, then you can use the self timer in combination with MLU. When you release the shutter, firstly the mirror locks up, and then either two or 10 seconds later the camera takes the shot.

I do use MLU when the occasion warrarnts it and have the MLU feature added to my My Menu.

Regarding in camera High ISO NR - if you shoot raw then the settings will not affect the raw data. They will only affect JPEGs if that is how you prefer to shoot. However, if you do shoot to raw, the High ISO NR does still get applied to the preview image, and the processing time to do that pointless exercise, if you have it set to STRONG will reduce your maximum burst capacity. See page 176 of the manual.

I have High ISO NR disabled and Long Exposure NR set to Auto.
 
cheers guys :thumbs:

although for what circimstances would i use MLU, macros on a tripod?
 
I switched it off as soon as I got the camera, but on some cameras I've seen NR makes the camera "busy" for quite a while after a shot, creating a delay before you can take the next shot. In party situations (high ISO) that can be a real difference.
 
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