Confused about landscape F-Stops

fracster

fracster

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Ade
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From what I have read on here, the majority seem to be of the opinion that F11 is ample for landscapes.Yet in "Digital Photo" landscape special, they advocate values of F16 and even F22, can somebody enlighten me on this please?

TIA.

Ade.
 
I read the same article and came away equally confused fracster. Seemed they didnt even consider the decreased IQ at f22 compared with using something like f11? :shrug:

I use my sigma 10-20 at f8 to maximise IQ and manage to keep everything in acceptable focus..........no one on TP ever suggests having a crack at f22

I'd go with TPers over digital photo anyday :)
 
Some of the most famous landscape togs will claim f11 is more than enough-point is what your camera can handle ref iq and amount of light on a lens- a fast lens with a constant f1.8 even at f16 will have more light qualityies than a f3.5 because the lens at the back of the lens-closest to the camera will be bigger and allow more light past even a smaller f stop-if this loses you then sorry.


Point is better quality=higher f stop number

less quality= lower f stop number.

Remember your lens will only focus to the longest point of focus and wil be in focus past infifnity anyway. the foreground interest is more to play with needing a high f stop.
 
Fair comment Ted........:D

I just wondered about why the two differing views...........:shrug:
 
You can answer the question for yourself. Take the same shot at different apertures and examine how sharp each image is. If the f22 is as sharp as the f11 /f13 then use f22 if you want to. If it is a bit softer then you are seeing the effect of diffraction and may prefer to stay with say f16 as a limit.
I'll normally go with something around f11 or f13 for landscape but I can't see any difference in sharpness at f22 on the 17-40 or 24-105 so I'll use f22 if I need the best depth of field or a slower shutter speed for water movement.
 
digitalmaniac said:
a fast lens with a constant f1.8 even at f16 will have more light qualityies than a f3.5 because the lens at the back of the lens-closest to the camera will be bigger and allow more light past even a smaller f stop-if this loses you then sorry.
Click to expand...

Erm, very confused.

Could you explain "light qualities" and why the lens closest to the body is bigger on a faster lens? Look at my lenses which range from f/1.4 to f/4 the size of the rear element seems pretty similar (the f/1.4 being the smallest). Isn't the size limited by the size of the mount?
 
yes it is, its not really to do with the size of the glass at the back of the lens but the total light getting through the lens, which - without telling anyone to suck eggs - lens speeds are in fractions of total light; f/2.8 or what ever.
lenses pretty much mostly tend to become fairly similar in quality (assuming the lenses are of the same line i.e. L lenses etc) around f/8-f11 regardless of the maximum aperture, we can all appreciate an f/2.8 lens will get a little sharper as you stop it down and may be 'better' than an f/4 lens at f/4...but reach f/8 and they'll be about the same.
I believe thats what digitalmaniac is getting at. its not to do with the size of the glass at the back...but it is true a fast lens does generally have a larger glass through which to project a greater quantity of light
 
Ok, makes sense sort of now. When I read "allows more light" I was thinking in terms of brightness not area and of course the larger glass is at the front of the lens not the rear.

Wondered if I'd been putting my lenses on backwards all these years :lol:
 
It may be that the journalist did not know what s/he was talking about.

If you know your lens is at its sharpest at a particular aperture, why not use it at that setting? Its very unlikely to be f22!

With a 28mm Zeiss lens on my Contax film camera I always used to use f5.6 because I knew it was good there, and with careful focusing could get it sharp from about 2 metres to infinity. That way I could often use it hand held. (O happy days!)

With a longer lens which has less depth of field I was obliged to use a smaller aperture (bigger f number) to get the same depth of focus. In which case I needed a tripod to get the longer shutter speed required.

Now you can change the film sensitivity of your digital SLR to get the same result.

I don't see the point of using f22 by choice unless you actually need a slow shutter speed for silky waterfalls or if it's almost dark!

The Ansel Adams's and Joe Cornishes of this world may habitually use f22 or even f45, but the lenses on the large format gear they use(d) have relatively short depths of field by their very nature.

I'm not sure if this sheds any light on the matter.;)
 
I tend to use f22 on most of my landscape shots, it's an aperture I'm comfortable with, that and ISO50, so inevitably a tripod is used.
If you use high quality glass, in the real world there isn't any noticeable difference in quality, the only downside is that dust bunnies are more obvious on a narrow aperture.
 
The physics of the situation is correct in saying that shooting with the lens stopped all the way down is not going to deliver optimum IQ. It is something that is becoming over played though.

If you need to use f22 or higher to get the shot you want, then go ahead and use it. A decent lens is going to produce a good image at any f stop and that's the more important thing to remember.
 
Les McLean said:
I tend to use f22 on most of my landscape shots, it's an aperture I'm comfortable with, that and ISO50, so inevitably a tripod is used.
If you use high quality glass, in the real world there isn't any noticeable difference in quality, the only downside is that dust bunnies are more obvious on a narrow aperture.
Click to expand...


It just seems odd that, if you're concerned about image quality (as you presumably are, shooting ISO50 and with good support), you'd go way past the point where diffraction softness kicks in and also go way overboard with your depth of field.

Whatever works best for you, I just can't fathom it personally.
 
robmiller said:
It just seems odd that, if you're concerned about image quality (as you presumably are, shooting ISO50 and with good support), you'd go way past the point where diffraction softness kicks in and also go way overboard with your depth of field.

Whatever works best for you, I just can't fathom it personally.
Click to expand...


Sorry, but I respectfully disagree, diffraction softness doesn't kick in so that it's noticeable (on good glass)

Also, f22 is not way overboard, just ask Joe Cornish, or any top flight landscape photographers who shoot with 35mm, f22 is commonly used.

I've used f29 on images that have been published, and once shot at f42, and the image was still acceptable.
 
hmmm i'd have thought a quick trial and error test would have answered this :D! I like to think that I take pictures and not camera settings, so whatever looks best (loads of help i know, lol)
 
Diffraction has a real and noticeable effect on IQ, at least when viewed at 100% magnification. Whether the effect is noticeable at the size you typically print/display your images is another matter. What is good for a 35mm full frame is not necessarily good for a 1.6X crop body, and the higher the pixel densities become - e.g. Canon EOS 50D - the earlier the effects of diffraction will manifest themselves, as diffraction softening extends the blur beyond more pixels. Point and shoots rarely go smaller than f/11 because it would be completely futile to do so.

Here is an album of test shots to demonstrate diffraction with ever shrinking apertures on a 40D, focused using Live View at 10X magnification with an L grade zoom lens....

http://picasaweb.google.co.uk/EezyTiger/POTNDiffractionTestWithFStop?authkey=zi1h_3k1k0s#

If you look up DOF values and hyperfocal distances using the online calculator here - http://www.dofmaster.com/dofjs.html - you will most likely conclude that you need nothing like f/22 for a crop body camera, for wide angle landscapes. f/8 or f/11 will probably be plenty, or f/16 at a pinch. f/22 on such cameras really makes no sense to me.

Knock the sharpness/DOF if you like, but this was shot at 17mm and f/2.8 on my 30D body. EXIF is in the image...

20080829_132224_2597_LR.jpg
 
tdodd-I think the comment you made on the picasaweb link is relevant

'So is diffraction a problem we need worry about in general, or only when pixel peeping?'

Perhaps f22 makes no sense to you, but it does to a large number of landscape photographers (me included)

At the end of the day, everyone to their own, if you are not comfortable with a narrow DOF, don't shoot at f22.
 
Les McLean said:
At the end of the day, everyone to their own, if you are not comfortable with a narrow DOF, don't shoot at f22.
Click to expand...

OK, let's look at the figures from the DOF calculator, assuming a 40D body and a lens at 17mm (27.2mm equivalent on full frame). That's towards the long end of the 10-22 and at the wide limit for most standard wide zooms...

f/2.8 - hyperfocal distance = 17.7' - near focus = 8.85'
f/4 - hyperfocal distancec = 12.5' - near focus = 6.25'
f/5.6 - hyperfocal distance = 8.88' - near focus = 4.44'
f/8 - hyperfocal distance = 6.29' - near focus = 3.145'
f/11 - hyperfocal distance = 4.47' - near focus = 2.235'
f/16 - hyperfocal distance = 3.17' - near focus = 1.585'
f/22 - hyperfocal distance = 2.26' - near focus = 1.13'

Optimum lens sharpness is probably around the f/8 mark, maybe nearer f/5.6 for a fast lens. Obviously any focal length under 17mm will just buy you even more DOF, so for a "standard" landscape shot with a crop body you would use f/22 why?

Even on a full frame body at 35mm (I'm thinking worst case scenario for DOF, with a 16-35 lens here) and f/8 you will have a hyperfocal distance of 16.9' and a near focus of 8.45'. f/22 will move those to 6.04' and 3.02', which is pretty darn close. Maybe f/22 makes more sense on a full frame body, but on a cropper I'm not so convinced.
 
Clearly Les needs another 4 inches :D

:coat:
 
Which aperture you shoot at really depends on what format you're using. FX digital might need f22 for a particular shot whereas on Four Thirds f11 would be ample. APS-C no doubt would fall somewhere in between, say f16. Diffraction is more likely to be noticable at very small apertures with smaller than full frame sensors.

Thus on my Olympus E3 I seldom go beyond f13 but on my Bronica ETRSi the aperture ring on every lens is practically glued at f22.
 
tdodd said:
Here is an album of test shots to demonstrate diffraction with ever shrinking apertures on a 40D, focused using Live View at 10X magnification with an L grade zoom lens....

http://picasaweb.google.co.uk/EezyTiger/POTNDiffractionTestWithFStop?authkey=zi1h_3k1k0s#
Click to expand...
I'm convinced.

As others have noted, different rules apply for different camera formats / sensor sizes, but this set of test shots strongly suggests that it's probably not a good idea to go beyond about f/11 on an APS-C camera.
 
Interesting article on diffraction limit here.

I think it is important to note that there is a difference between a whole image looking a bit soft and there being an obvious difference in sharpness through the image due to DoF.

Paul
 
Can I just remind people that whilst we all obsess over sharpness these days, its predominantly because we can get 100% blowup, that's the equivalent of looking at slide film with a microscope (people did it!)

When everyone shot film, unless you were blowing things up to the size of a billboard, you weren't going to be able to see tiny degradations of sharpness on 35mm.

Stop obsessing over a minute change, and get on with enjoying your togging!
 
Carried out a small experiment, took three identical images of the house wall, at f5.6, f11 and f22.
Canon 1dS MKII, with a canon 50mm f1.4 lens, tripod mounted, ISO100, timer and central focus point.

brought the raw images up exifpro, and took a screen grab of each, so it's a screen grab of each raw file before any processing whatsoever, I've included the shooting info in each screen grab.

First set at around 100%
F5.6
f5.6s.jpg


F11

f11s.jpg


f22

f22s.jpg


Second set of the top corner at 600 %

F5.6
f5.6600s.jpg


F11
f11600s.jpg


f22
f22600s.jpg


Larger image links
http://www.lesmclean.co.uk/aperture/f5.6.JPG
http://www.lesmclean.co.uk/aperture/f5.6600.JPG
http://www.lesmclean.co.uk/aperture/f11.JPG
http://www.lesmclean.co.uk/aperture/f11600.JPG
http://www.lesmclean.co.uk/aperture/f22.JPG
http://www.lesmclean.co.uk/aperture/f22600.JPG

Now my eyes are maybe getting old, but I couldn't see any significant difference between f5.6, f11 or f22.

So I reckon (regardless of what's been said) , the real world difference is negligible, as long as you are using decent glass.

I accept that this was taken on a full frame camera, therefore a cropped camera may be different.

Also I did notice a slight softening (very slight) at f22 when blown up to 1500 %, but as that kind of enlargement would be rarely used, so surely not an issue.
 
Surely the simple point is to pick the aperture that gives you the DoF you require and that's good enough

As tdodd was pointing with the DoF scales, if the job is done at f8 because everything 2ft to infinity is sharp, and there is nothing closer than 2ft, then there's no point at all using f22 - added to which it may soften the image a smidge or increase the risk of camera shake

If however you need the foreground sharpness to start just 6" from your lens, then f22, f32 and the possibility of diffraction issues is far better than a 'sharper' image at f8 that's OoF !!!

I love my 12-24mm for landscapes and I love having a very close subject matter too as foreground interest, but as the DoF is so huge anyway with a bit of hyperfocal focussing I rarely need or use anything smaller than f8-f11 - which just happens to be where this lens is sharpest anyway = job done :thumbs:

DD
 
I'm not sure why there needs to be so much confusion. It is a fact of physics, completely unrelated to the quality of your lens, that when light passes through small holes/gaps it becomes diffracted and spreads over a wider area. In other words, it becomes slightly defocused. The smaller the gap, the bigger the effect. This is explained very well in the article referenced in post #22.

For any given aperture, the spread is the same regardless of the size of your sensor or the density of the pixels. The thing that makes the differences apparent is the amount of magnification required to display the image at the size you want to view it at. Let's say you wanted to make a 10x8" print from your image file. In mm that is 254mm x 203mm.

The sensor on a 1Ds3 is 36mm x 24mm. To magnify the image on the sensor to fit 254mm x 203mm you would have to increase the image size by 254/36 = 7.06X.

The sensor on a 40D is 22.2mm x 14.8mm. To make a 254mm x 203mm print you would have to increase the image size by 254/22.2 = 11.44X, which is a much higher degree of magnification. In fact it is a magnification factor 1.62X greater (the crop factor!).

Well the problem when you blow up the image from a small sensor is that you have to magnify it more to get the same end result. When you magnify the captured image you also magnify the blur caused by diffraction, movement, poor focus or anything else. This is why diffraction softening is more evident in images captured on a crop body compared to a full frame body, and is also why medium and large format cameras allow you to use even smaller apertures without a problem - you are magnifying the softness far less on larger formats.

Hence, in my opinion, while f/22 is absolutely fine for full frame sensors, f/16 is a better limit for 1.6X crop bodies, and f/11 will yield sharper results still. Of course, if you print no larger than 6"x4", or resize for display on the web, then it honestly doesn't matter whether you use f/16 or f/22.
 
To continue a bit further, when you view an image at 100% on your screen, you are, of course, mapping one image pixel from the sensor to one display pixel on your monitor. Put simply, the more megapixels your sensor has, the larger the virtual image is that is created by viewing at 100%. In other words, the more megapixels you have, the more you are magnifying the overall image size when you view at 100%. That is why the softening will appear worse on a 50D than a 40D than a 30D for any given aperture.

There is also a question of a threshold beyond which diffraction softening is visible and before which it is not. While the diffraction softening is small enough to remain within the confines of a single pixel there will be no difference between any of the cameras. However, once the diffraction softening begins to increase it will manifest itself first in the camera with the smallest pixels - the 50D, wihile the 40D and 30D may still be safe. The 40D will be next to crack, and the 30D will be most immune to the effects of diffraction softening because the sensor resolution will be more of a limiting fator than the diffraction, for a while at least.

Once you stop viewing at 100% and view at a magnification to actually fit the whole image on your screen then the differences should all but disappear and a 50D image should look much like a 40D image, which will look much like a 30D image, so long as there were enough pixels to go round in the first place.
 
:agree: again

But if you NEED the DoF of f22 and it's a crop sensor, it's still better to use it than not take the shot or have part of the shot OoF instead

It's just best to use the widest aperture that does the job, as this reduces the diffraction issue and also gives a higher shutter speed/lower ISO to improve IQ still more

Good thread this chaps :thumbs:

DD
 
I reckon you guys should start writing articles for digital Photo! Learnt way more about F stops for landscape photography in this thread than I did shelling out £4 for their mag! :D
 
Holy Moses..................:thinking:

I think i`ll leave it at F8, seems easiest............:D

But thanks for all the input,certainly got me thinking.
 
I tend to use around f16 as a compromise - I have noticed a slight softness creeping in at f22 (dealing in whole f-stops here) but then after a bit of tinkering you'd be hard pressed to notice the difference in IQ from most stops used. f22 and iso 50 tend to be reserved for the long exposure/water movement effect shots on bulb setting where everything but the water is in focus and the desired effects come out thanks to the long shutter speed. in good light f16/100iso and a tripod can't do you too wrong which ever way you look at it...
f8, f11, f16, f22? use sharpening and it'll all be pretty much the same, especially at 99% of print sizes. or just get you face away from the screen cause its not good for your eyes to be that close.
 
Picked up an Amateur Photographer mag that was lying around the house. it's the Christmas 2007 edition (I know it should have been thrown out yonks ago)
In it there is an article by Adam Burton, arguably one of UK's best landscape photographers, of the 10 images in the article, none were taken with a wider aperture than f16, 4 at f16, 3 at f19 and 3 at f22, all were taken with a canon 5d. In the same mag, Charlie Waite had an article on black & white, of the two landscape type images taken with a DSLR, one was at f22.

So, if two of the best landscape photographers in the UK are comfortable shooting at f16-f22, then the reasoning is, it must be OK, they wouldn't sacrifice the quality they are renown for.

I think you will be restricting yourself creatively by not shooting at any aperture smaller than f8 or f11, unless of course you don't intend to shoot landscapes.
 
Perhaps they wanted to slow the shutter down for some reason? Or have incredibly close foreground subjects?

Fact is... if f8 gives you all the DoF you want and slowing the shutter down isn't an issue, then f8 is better than f22 as it is sharper

I shoot my landscapes on Nikon's 12-24, and simple fact is the DoF anywhere near 12mm is so huge f22 doesn't give me anything over f8, yet according to reviews it is softer at f16 & f22 - hence f8 being the highest IQ and more than enough DoF is the one to go for

DD
 
slow the shutter via three methods; increased f/ stop, decrease ISO or slap on a filter.
after forking out for expensive glass the last thing you'd want to do is put excessive filters (beyond the grads etc) up front as that does affect IQ, even the really expensive ones - its an extra surface for light to go through after all, so to maintain IQ its easier to stop down...
...unless this is a completely ridiculous line of thinking ?
 
DiddyDave said:
Perhaps they wanted to slow the shutter down for some reason? Or have incredibly close foreground subjects?

Fact is... if f8 gives you all the DoF you want and slowing the shutter down isn't an issue, then f8 is better than f22 as it is sharper

I shoot my landscapes on Nikon's 12-24, and simple fact is the DoF anywhere near 12mm is so huge f22 doesn't give me anything over f8, yet according to reviews it is softer at f16 & f22 - hence f8 being the highest IQ and more than enough DoF is the one to go for

DD
Click to expand...


The only image (in Adam Burton's article) that particularly needed a slow shutter speed was of a waterfall, and that was 16sec @ f22, so in theory he could have shot at f11 or f8 and still had a slow enough shutter speed to smooth the water out.

All the images (except one) were taken in the 20-28mm range.

The reality of it is (regardless of the discussion), shooting at f16-f22 is generally the norm rather than the exception for recognised landscape photographers. Saying that, they are generally shooting with FF cameras and the lenses are usually top glass.
 
I don't get what you're saying Les???

If the foreground fencepost is perfectly in focus, as is the far line of hills, and all at f8 (i.e. most lenses highest IQ), are you saying you'd still stop down to f22???

If so, why?

'Proper' landscapers must have a reason for it, but if it's not DoF it has to be shutter speed and if not that - where's the point as you're introducing more chance of diffraction and risking camera shake/subject blur

Of course I accept that 28mm on a FF may well mean f22 is needed to get the DoF required, but if f11, f8 or even f5.6 did the same DoF job using anything 'slower' is pointless - isn't it ??? :thinking:

DD
 
camera shake and blur? you forget 'proper' landscape photographers use a tripod and MLU...
 
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