Canon announces EOS 7D ***Official Discussion thread***

I'm sure hoppy will correct me if i'm wrong as he seems to be very knowledgeable, but depth of field is affected by focus distance so in your 5d vs 7d with the same lens at the same distance then the 7d will likely have the SHALLOWER DoF (BETTER BOKEH) as you will be focusing closer.
 
Thought I would join in this as an enthusiastic amateur!! I will almost certainly upgrade from my 40D once I have seen some reviews and the price has softened.

I thought that this may be of some interest(I used CPB as a good real price point verus Canon rrp)

CAMERA LAUNCH DATE RRP @ 01/09/09 CPB @ 01/09/09 %

EOS 40D 01/09/2007 £940 £550 59

EOS 50D 01/09/2008 £1,370 £730 53

EOS 5D MK2 01/10/2008 £2,690 £1,790 67

EOS5000D 01/05/2009 £870 £520 60

EOS 7D 01/10/2009 £1,700 N/A N/A


So what does this tell us? Perhaps that we can expect the 7D to get down to £1100 in a few months?


Incidentally I have Sigma 10-20 Canon 100-400L and about to purchase Canon 24-105L to replace kit 17-85.

Anyway hope this helps!!
 
coldpenguin said:
Hmm, that would be my problem then. I am thinking birding, where (in many cases) you can't get close enough. Thus the extra 'reach' added by a crop camera doesn't effect the DoF, only the FoV. There shouldn't be any difference in two shots taken with the 7d, and 5d, from the same place, with the same lens, if the 5d is later cropped to include the same frame?
Perceived DoF may change on the larger image, but if the lens is held in the same place, the size of the sensor (assuming that this distance to the focal point of the lens doesn't change), shouldn't matter.
The sensor could be thought of as a projector screen at this point, just because you roll it down further, doesn't change the picture? Something else must be going on here, rather than just changing the size of the sensor. They must be moving it closer to the mount at the same time.
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If you frame up a bird with a 500mm f/4 lens, the image will be the same size regardless of the camera format. But if you fill the frame with the crop camera, you will need an 800mm lens to do the same on full frame, and in that case your depth of field will reduce by a factor of 1.6x also, ie 1.28 stops, due to the extra magnification.

Put another way, if you shoot on full frame but enlarge the centre of the image to match the crop picture, you will also gain extra depth of field by the same amount.

Depth of field calculations assume that no cropping of the image occurs. If you do crop, then you are effectively reducing the format size and doing that increases depth of field. Sure, you have to enlarge the reduced size of image more to regain print size, but that doesn't level the playing field - you still get more DoF with smaller formats.

With compact cameras the effect is substantial - the average compact has a crop factor of about 5x relative to full frame.
 
jon- said:
I'm sure hoppy will correct me if i'm wrong as he seems to be very knowledgeable, but depth of field is affected by focus distance so in your 5d vs 7d with the same lens at the same distance then the 7d will likely have the better DoF as you will be focusing closer.
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LOL Jon ;) The first half of your post is absolutely true; the second half contradicts itself :)
 
HoppyUK said:
LOL Jon ;) The first half of your post is absolutely true; the second half contradicts itself :)
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You mean the part with me calling you knowledgeable ;)

I read it as this:

Bird 20 metres away. Camera not moving.

7d with 400mm @ f4 fills the frame (ie 640mm)
5d with 400mm @ f4 doesn't fill the frame, so needs to crop down.

The depth of field would be SHALLOWER!!! on the 7d as the glass is effectively focusing closer for the cropped body. Or is that still crap? :)

Haha, I've just realised I've been saying better DoF when i meant better Bokeh!!!! I MEANT SHALLOWER DoF!!! Bloody friday afternoons :)
 
jon- said:
You mean the part with me calling you knowledgeable ;)
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Correct :)

I read it as this:

Bird 20 metres away. Camera not moving.

7d with 400mm @ f4 fills the frame (ie 640mm)
5d with 400mm @ f4 doesn't fill the frame, so needs to crop down.

The depth of field would be better on the 7d as the glass is effectively focusing closer for the cropped body. Or is that still crap? :)
Click to expand...

Still crap :lol: Forget the 640mm bit, that's a cropping effect - the lens hasn't changed, and neither has the image it forms, nor the focusing distance, nor the focal distance or anything else. If you crop the 5D image to match the 7D pic, they will be identical in terms of DoF.

It is only when you fit a different lens (or change the image magnification in some other way, ie move closer) that DoF changes. For example, to get identical framing with a crop camera and 400mm lens, you would need a 640mm lens on full frame. Now, because the full frame sensor is much bigger, the magnification has increased to fill it, and that is what is affecting DoF, ie it is reduced.
 
HoppyUK said:
If you crop the 5D image to match the 7D pic, they will be identical in terms of DoF.
Click to expand...

I just checked the link to DoF calculator you sent.

According to that at 55mm f16 a subject 10 meters away will have a DoF of 6.61ft with a cropped body and 12.3ft on a full frame. :thinking:
 
LOL. Nice to see you guys havin' fun! :D

Hopefully here's a practical situation and visual representation of what these different sensor options mean in real money...

This Kingfisher shot was taken at 6.50a.m. in pretty poor light even for that time in the morning. The range was a good 60 feet - frustratingly -just too far even for the 50D with 500mm and 1.4X TC. (700mm or 1120mm if you want to figure in the crop factor) ISO was 800.

3887657224_4640d678fe_o.jpg


Not surprisingly, the best crop I could get from this shot showing the bird a reasonable size in the frame for web use at 800 pixels was just about acceptable at that size, but far from the quality I'd have preferred. The point I'm trying to make is that there simply isn't another camera in the Canon range which could have even got close to producing a reasonable shot at the same range and with the same lens. Even going longer with the lens wouldn't necessarily have been any advantage with less pixel density, and in some cases would be worse despite the increased 'apparant' reach.

3887745666_6caab5d512_o.jpg


The 7D now brings a further 3 million pixels to the table which isn't insignificant. It wouldn't have turned my Kingfisher shot into a masterpiece, but it would have added welcome resolution to that final cropped image had I had it at the time.

These crops show the the maximum subject size I could have recorded that Kingfisher at (full 1:1 file size) from each of the following cameras. Obviously, they're not 100% crops, but they are to scale.

3887949307_03df0402b9_o.jpg



If you're into wildlife photography, you really need to get a grasp of what these sensor sizes and pixel densities mean before you go and spend a whole load of wonga on your next camera.

Of course, the closer you can get to your subject and the more you can increase his size in the viewfinder, the less these differences matter, but the fact is you just can't get that close, not with any regularity, and the more reach you have the better in most situations.

EDIT.

I've been asked to add the 1DSMK3 and 5DMK2 into the above comparison chart. There are actually slight differences in sensor size between the two but so slight as to make little difference.
 
Just don't get yours before me then Sara. ;)
 
anyone have an idea of when we will see real life tests of this? Think i am still going to go for 5D2 as it performs better at higher iso. Not by huge amounts but possibly enough to make a difference. I shoot live music and Skateboarding so the 7D would be great for most things, but will prob keep my 40D for the skate and 5D2 for live music, unless anyone has other suggestions?
 
swag72 said:
Great post Cedric and well illustrated - Thank you. Definately set my mind on the 7D :thumbs:
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yes this really shows what the diffrence is.
Thanks from me as well.
Rob.
 
Not wishing to hijack the thread but...
I'm hoping to see a few 50D's in the for sale section when people start buying the 7D :D
 
CT said:
Hopefully here's a practical situation and visual representation of what these different sensor options mean in real money...
Click to expand...

Great post Cedric. Thanks :thumbs:

jon- said:
I just checked the link to DoF calculator you sent.

According to that at 55mm f16 a subject 10 meters away will have a DoF of 6.61ft with a cropped body and 12.3ft on a full frame. :thinking:
Click to expand...

Not sure what you've got there Jon, but here are some figures from www.dofmaster.com of the changes when using a 1.6x crop camera such as the 7d, and a full frame camera.

a) Starting set up:
7D, 100mm, f/8, focus 3m, DoF 26.5cm.

b) Same framing with longer lens on larger FF format, same f/number, same distance, gives reduced DoF:
FF, 160mm, f/8, focus 3m, DoF 16cm.

c) As above, but increase f/number 1.25 stops (closest setting), DoF restored to same as start point:
FF, 160mm, f/12.7, focus 3m, DoF 25.4cm.

You can also get the same framing with FF, as in b), by moving closer instead of fitting a longer lens. If you do that DoF will be the same as if you had fitted the longer lens, ie reduced to 16cm, but perspective will also have become more pronounced and field of view increased because of the closer distance.

It sounds complicated when explained like that! Sorry - best I can do ;)
 
I've been asked to add the 1DSMK3 and 5DMK2 into the comparison chart above.
 
Theres some hi res images on dp review now, High ISO noise handling looks impressive.
 
HoppyUK said:
Great post Cedric. Thanks :thumbs:



Not sure what you've got there Jon, but here are some figures from www.dofmaster.com of the changes when using a 1.6x crop camera such as the 7d, and a full frame camera.

a) Starting set up:
7D, 100mm, f/8, focus 3m, DoF 26.5cm.

b) Same framing with longer lens on larger FF format, same f/number, same distance, gives reduced DoF:
FF, 160mm, f/8, focus 3m, DoF 16cm.

c) As above, but increase f/number 1.25 stops (closest setting), DoF restored to same as start point:
FF, 160mm, f/12.7, focus 3m, DoF 25.4cm.

You can also get the same framing with FF, as in b), by moving closer instead of fitting a longer lens. If you do that DoF will be the same as if you had fitted the longer lens, ie reduced to 16cm, but perspective will also have become more pronounced and field of view increased because of the closer distance.

It sounds complicated when explained like that! Sorry - best I can do ;)
Click to expand...

I understand you perfectly, I think you're still miss understanding me.

Someone many pages back was asking about the extra reach you get with the crop for twitching.

His example was a bird lands in a tree X metres away. X is a constant. How much of an advantage would the crop be.

Well we both agree the crop would frame the bird better as you get more reach. He then asked if he took the shot using the 5d from the same distance as the 7d, would he be able to crop down in POST the 5ds image to look like the 7d.

The answer of course is yes, but there would be differences in the final image. The 7d's correctly framed, uncropped image would be of a better resolution for starters. The 7d would also have less depth of field, and better bokeh as the lens would have focused closer relative on the 7d relative to the 5d.

dofmaster seems to confirm all this.

Do I (finally) make sense to you now? :)
 
jon- said:
His example was a bird lands in a tree X metres away. X is a constant. How much of an advantage would the crop be.

The answer of course is yes, but there would be differences in the final image. The 7d's correctly framed, uncropped image would be of a better resolution for starters. The 7d would also have less depth of field, and better bokeh as the lens would have focused closer relative on the 7d relative to the 5d.
Click to expand...

If X is a constant then neither lens has focused any closer than the other.

If you take a full frame image and crop it in software to make it equal in composition to the same image shot with a crop body camera (shot at the same distance, X, with the same focal length, Y) then the DOF will be the same. It makes not a scrap of difference whether your camera body and sensor does the cropping (hardware crop) or you crop in software.

The missing ingredient from the discussions above is the final enlargement factor to produce a print (or onscreen display) of a given size - say 12"x8" - from the image you captured. The reason a full frame image has greater DOF, for the same values of X and Y, is that there is less enlargement required to get from your full frame image (36mmx24mm) to 12"x8" than to get from your cropped image (22.3mmx14.9mm) to 12"x8". The extra enlargement required for the cropped image is what means it actually has less DOF than full frame for any given value of X and Y.
 
that's a VERY nice demonstration of the real worl CT. makes my 1 II feel a tad inadequate though. :lol:
 
dazzajl said:
that's a VERY nice demonstration of the real worl CT. makes my 1 II feel a tad inadequate though. :lol:
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LOL. I know -I loved my 1DMK2n but the game has moved on out of all recognition and so fast too!

When you look at where the 1DSMK3 and the 5DMK2 sit in that chart, you can argue a good case for an all round camera as they're not far behind the 40D for copping and still have all the full frame advantages for other stuff. I did consider going that route at one stage. Who'd have thought though that in the space of less than 12 months Canon would have introduced the 50D and the 7D pushing the pixel count to these heady limits and just putting the crop advantage streets ahead of everything else!

It seems a certain sign of Canon's commitment to the 1.6 crop sensor and you just wonder where it's eventually leading, and how it will affect other models in the range.
 
I think that someone has either mis-labelled the photos, or those on dpreview are noise-reduced.
There are samples they have taken on page 14 of their Review
 
CT said:
LOL. I know -I loved my 1DMK2n but the game has moved on out of all recognition and so fast too!
Click to expand...

I still think the 1DMk2 can hold its own. The AF system is very good and its metering system is still way ahead of the 40D (not used a 50D but I'd expect it's the same as the 40D).

I do fine the 8 megapixel count is limiting especially with it being 1.3x crop as well, the blacks are noisey and I wouldn't like to go above ISO 400 but I still use it over my 40D everytime.

When I get my 7D the 1DMk2 will become my backup camera and the 40D will be sold.
 
I have to admit I'm definitely being sold by the 7D, my only worry being that I get the 7D and then a 'blow you away 1D MKIV tech specs' is released.

Mmm choices choices.
 
If the 7d has got everything you want and it does the job why worry about the 1d mk4 specs its another camera and there will be a better one than that in a1d mk5 when that comes out
Regards
Lost
 
I'm in a real quandary over this camera :thinking:

I was already in a tizz about the choice of a 5dmk2 or 1dmk3

Both have distinct benefits for my photography and now the 7d adds others :eek:

I need better high ISO quality than my 5d currently allows
Better AF performance than my current 5d
Better metering than the 5d

The 1d and the 5d both have the larger sensor against the 7d's aps-c

Canon should shuffle off rather quickly and come back with a 5dmk3 :D
 
digitalfailure said:
I'm in a real quandary over this camera :thinking:

I was already in a tizz about the choice of a 5dmk2 or 1dmk3

Both have distinct benefits for my photography and now the 7d adds others :eek:

I need better high ISO quality than my 5d currently allows
Better AF performance than my current 5d
Better metering than the 5d

The 1d and the 5d both have the larger sensor against the 7d's aps-c

Canon should shuffle off rather quickly and come back with a 5dmk3 :D
Click to expand...

a 1DsMkiii sounds like the camera for you...the only down side is costs.
 
you're right it does :gag:

I could stretch to a 1dmk3 but not a 1dsmk3....i'd have to be earning a serious wedge from photography before I even thought about the flagship beastie.
 
CT said:
Damn- that AF system looks impressive!!
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You should see what Nikon can do then!

Thats a cut down version Nikon's 51 point AF system that has been in the D300/700/3/3X for now two years...
 
desantnik said:
You should see what Nikon can do then!

Thats a cut down version Nikon's 51 point AF system that has been in the D300/700/3/3X for now two years...
Click to expand...

LOL. Why should The Devil have all the best tunes? :shrug:

Just to be a little pedantic - only 15 of those 51 points in the Nikon are cross type, whereas all 19 are cross type in the 7D. ;)
 
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