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Pixel Density and Reach--Any Definitive Tests?

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bhollis said:
Interesting. What ISO were these shot at? Do you have samples you could post shot at ISO 200 without NR. That way we could compare them more directly with Liquidstone's results.

Thanks.
Click to expand...
This particular test was done at 800 ISO.

I am currently writing up a 2-part series that I will publish on my website in the next few days.

I'll try to address everyone's issues/suggestions, but the bottom line is that after equalizing things out after cropping and NR, the differences are so small that (in my opinion) one should focus their attention on other attributes of all three cameras and use those attributes as their primary reason for choosing the camera in a focal-length-limited scenario.

No matter, I do find these comparisons in a focal-length-limited scenario as important. All comparisons found on this web site as well as others don't compare cameras in a focal-length-limited environment and since I spend most of my time photographing birds, I find these tests very relevant.

I'll be sure to let everyone here know once I have published my findings.

Alan
http://www.iwishicouldfly.com
 
These tests are with static subjects. When it comes to real world conditions, i.e. moving subjects as in BIF, AF speed/accuracy, FPS will certainly make a difference in keeper rate.
aayjay said:
bhollis said:
Interesting. What ISO were these shot at? Do you have samples you could post shot at ISO 200 without NR. That way we could compare them more directly with Liquidstone's results.

Thanks.
Click to expand...
This particular test was done at 800 ISO.

I am currently writing up a 2-part series that I will publish on my website in the next few days.

I'll try to address everyone's issues/suggestions, but the bottom line is that after equalizing things out after cropping and NR, the differences are so small that (in my opinion) one should focus their attention on other attributes of all three cameras and use those attributes as their primary reason for choosing the camera in a focal-length-limited scenario.

No matter, I do find these comparisons in a focal-length-limited scenario as important. All comparisons found on this web site as well as others don't compare cameras in a focal-length-limited environment and since I spend most of my time photographing birds, I find these tests very relevant.

I'll be sure to let everyone here know once I have published my findings.

Alan
http://www.iwishicouldfly.com
Click to expand...
 
Alan, I followed this similar heated discussion over at BPN which I believe you contributed. One request if I may. Can you use ISO100 for your comparisons? This might take away the noise disadvantage of the 7D. It would still be nosier but perhaps the inherent resolution advantage would be more apparent. People need to remember that resolution tests are done with a high contrast target not something that has only 10-20% contrast difference like some bird feathers.

I am not jumping for joy over your results since I just ordered my 7D with "reach" being teh main reason.
--
A bird in the viewfinder is worth...
 
Yes if you do BIF then "reach" might not be your main concern. But for static birds then "reach" maybe an issue. These tests do demostrate under what conditions a potential advantage could be obtained with the 7D. Probably ISO100 is going to be required. Alans tests may hopefully show this.
--
A bird in the viewfinder is worth...
 
What I take away from this interesting discussion is that lens quality, sample-to-sample variation (both camera and lens), degree of cropping, focusing and exposure accuracy, ISO speed and raw conversion+PP will combine to make significantly more difference than the choice of camera, especially when looking at prints (as opposed to 100% screen crops).

I still believe that any of the recent models mentioned here will do the job, and that camera choice between the 7D and 5D2 (from the OP) should be based primarily on factors other than pixel density. Even back in the film days, producing a highly-detailed cropped photo required more than simply using a finer-grained film.
 
aayjay said:
But knowing that some may claim that adding the 1.4x TC will reduce the sharpness, I again ran this test with the Canon 600mm lens w/o a TC. In the second test, I used ISO 100 through 12,800. Results were similar.

As a third test, I used my Canon 70-200 f/4 IS lens. Results were the similar.
Click to expand...
There must be something seriously wrong in your tests. The higher resolution of the 7D compared to the 5D2 should be easily visible at lower ISO. BTW, I have a 5D2 and a 60D and I know that from own experience.
aayjay said:
Also, please note that I did state that prior to adding noise reduction, the 7D's image was slightly sharper, but with more noise.
Click to expand...
No, the 7D has higher sensor efficiency than the 5D2 and should have less noise on the image level in your test.
 
schmegg said:
But, of course, you wouldn't need the TC with the 7D, ...
Click to expand...
Yes, in this test shooting with the 7D should result in similar subject resolution as with a 5D2 with 1.5x TC.

I don't think anybody is arguing that TCs are useless for bird photography with good lenses - quite the opposite! I find it very odd that a highly experienced bird photographer is arguing that the 7D does not provide useful extra reach compared to a 5D2 in a focal length limited situation.
 
Phil Hill said:
What I take away from this interesting discussion is that lens quality, sample-to-sample variation (both camera and lens), degree of cropping, focusing and exposure accuracy, ISO speed and raw conversion+PP will combine to make significantly more difference than the choice of camera, especially when looking at prints (as opposed to 100% screen crops).

I still believe that any of the recent models mentioned here will do the job, and that camera choice between the 7D and 5D2 (from the OP) should be based primarily on factors other than pixel density. Even back in the film days, producing a highly-detailed cropped photo required more than simply using a finer-grained film.
Click to expand...
Agreed, and a big fat +1 for this:
Phil Hill said:
...raw conversion+PP will combine to make significantly more difference than the choice of camera...
Click to expand...
If I were to pick one today, it's be a difficult choice. But since I got the 5DII before the 7D was released, my choice was made already. However, reading this and similar threads, makes me less inclined to add a 7D to my lineup. OT - Pardon me whilst I enter a fantasy-land where used 1DIVs drop below $3k after the 1DX is released...

Seriously though, we should all ENJOY and LEARN to maximize the potential of the gear we have.

Cheers,
GT

--
Lyin' Pete used to do this all by touch...
 
Many people that I've seen in events use the 5D2 for stills and the 7D for video. The APS-C format, being closer in size to the Anamorphic, half 35mm frame format, has a DOF closer to what you see in Hollywood movies. That was mentioned in the latest "Cinematography for Photographers" tutorial video from Michael Reichmann and Chris Sanderson.
Alton (TN) said:
I'm counting the days until I can buy a 7D. I have the 5D2 and love it, and I needed it first for some of the events that I shoot. Lately, I have moved more into wildlife, particularly birding, and in my mind I could use the extra reach, pixel density, or whatever the perception of the 7D advantage is.

Of course the 7D would be useful for Upward basketball and a few other sports that I shoot and I look forward to the AF and fps it has over the 5D2.

As it stand right now, the 20D is my backup so it is time for an updated body. In my mind the 7D compliments the 5D2 perfectly.

As someone who is getting ready to pull the trigger on a 7D this thread has been pleasantly civil and informative. Thanks to those who contributed!
--
Alton
Click to expand...
--
Martin Ocando
-------------------------

 
aayjay said:
bhollis said:
Interesting. What ISO were these shot at? Do you have samples you could post shot at ISO 200 without NR. That way we could compare them more directly with Liquidstone's results.

Thanks.
Click to expand...
This particular test was done at 800 ISO.

I am currently writing up a 2-part series that I will publish on my website in the next few days.

I'll try to address everyone's issues/suggestions, but the bottom line is that after equalizing things out after cropping and NR, the differences are so small that (in my opinion) one should focus their attention on other attributes of all three cameras and use those attributes as their primary reason for choosing the camera in a focal-length-limited scenario.

No matter, I do find these comparisons in a focal-length-limited scenario as important. All comparisons found on this web site as well as others don't compare cameras in a focal-length-limited environment and since I spend most of my time photographing birds, I find these tests very relevant.

I'll be sure to let everyone here know once I have published my findings.
Click to expand...
Great. I'll look forward to seeing your results.
 
clk_walker said:
I need the image larger to se these differences. Using native monitor resolutions is not the answer. Since this is a 100% crop it will be pixel for pixel. Never mind how big the pixel is. I tried a magnifying glass which helped alittle. But really. If the full image was printed to say 8x10 would anyone notice the differences?

i was hoping to get my 7D today but no one home we person came. So Thrusday at the earliest. I will immediately be doing some backyard bird shots to compare with 20D.
--
A bird in the viewfinder is worth...
Click to expand...
maybe you are far-sighted? have developed cataracts?
 
Based on feedback, I have written a 3-way comparison between the 5DM2, 7D and 1D Mark IV in a focal-length-limited test. I used the Canon 600mm f/4 IS to perform the test without a teleconverter and used various ISO settings: 100, 400, 800 and 1600.

Part I of the test can be found here:
http://iwishicouldfly.com/iwishicouldfly/journal/html/020112.html

Part II of the test can be found here:
http://iwishicouldfly.com/iwishicouldfly/journal/html/020112b.html

Please be aware this test is only valid for a focal-length-limited scenario and does not take into consideration other features (or lack thereof) of these cameras which I feel are more important attributes than the image quality produced from all three of these cameras.

Nonetheless, I think it's an interesting comparison.

Enjoy!

Alan
http://www.iwishicouldfly.com
 
Good test. I'll be interested in reading the comments. I think that most will be able to pick the camera order, based on resolution and noise. I also agree with your conclusion that all 3 are capable of capturing excellent detail and users are best served by choosing one of these cameras based on other characteristics (e.g. FF, FPS, AF, cost...) that fit their needs. It also make it easier for me to wait (until next year?) for the 7DII and continue to 'get by' with my 5DII.

Thanks for taking the time to conduct and post this test.

Cheers,
GT
 
Hiya, this was an interesting consideration, so I figured I'd do the tests for myself also. All things equal. All I did was swap bodies on the back of the lens. Each shot was taken at ISO 100, F4.0, 0.6sec (poor light), 400mm. On tripod, no IS, Mirror lock up. Opened in ACR, synchronized. No sharpening, no noise reduction, no level adjustments. These are the results. In some crops it's almost a case of camera out resolving the print quality of the note..... But for me the difference is obvious. With reach in the equation the 7D clearly out resolved the 5DII.

5DII original (downsized).





Equivalent 7D original (downsized).





5DII 100% crop, bottom left.





7D equivalent, 100%





5DII 100% crop centre.





7D equivalent, 100%





5DII 100% crop, top right.





7D equivalent, 100%



 
aayjay said:
Nonetheless, I think it's an interesting comparison.
Click to expand...
Definitely interesting.

One thing that is evidently different between the two tests is that Romy has cropped the image much more aggressively whereas you've used a much larger part of the frame for your comparisons.

Compare your target crop area to the 5DII's frame - it's possible to crop the 7D image to roughly that same ratio. I'm thinking that the 5DII's image would really start to struggle if you cropped it to that size - which is what Romy is showing.

It seems you have chosen a cropped image size that allows the 5DII to compete - a crop which is barely smaller than the full 7D image. This hardly represents a reach limited scenario for the 7D!

So - based on this, the 7D definitely does have a reach advantage - it's just that your not looking that hard for it ;-)
 
Good test Alan. The 7D images looked alittle more detailed, i.e., contrast, for the upper part of the feather. You didn't mention how you focused? Manual Live View?

If one is trying to do a test to show absolute resolution differences among the three bodies then this is not the test. Shoot a paper note. But I haven't seen too many paper notes in the wild.
--
A bird in the viewfinder is worth...
 
Nice test. To show comparable results to Alan's you should resize both images. No doubt that the absolute resolution of the 7D is better than the 5DII or the 1DIV. However, resolution is always compared against high contrast subjects like the print on your paper note. Alan's test was more about differences against real subjects, i.e., bird feather. I was hoping that the differences between the 5DII and 7D would be more significant since I just got a 7D for its "reach" advantages.
--
A bird in the viewfinder is worth...
 
Thanks!

To answer your questions, I used Live View and took 3 images per ISO setting just to be sure I got the best of the best.

The reason I did not choose to do a paper note or a resolution chart is that I feel the blurred background noise is just as important as resolution in computing the total quality of an image. It's harder to see the noise in a totally sharp image vs. that which contains a blurred background. Quite typical when photographing birds in the wild.

I haven't seen too many paper notes in the wild either, but if I did I'd be chasing after them. Screw the bird! ;)
clk_walker said:
Good test Alan. The 7D images looked alittle more detailed, i.e., contrast, for the upper part of the feather. You didn't mention how you focused? Manual Live View?

If one is trying to do a test to show absolute resolution differences among the three bodies then this is not the test. Shoot a paper note. But I haven't seen too many paper notes in the wild.
--
A bird in the viewfinder is worth...
Click to expand...
 
Great test, thank you for doing it.

Just one remark - when you say that you resize to 400DPI, I have no idea what that means. What is the uprez coefficient for the 7D image, for example?
 
bhollis said:
a final image comprised of 8MP from the 5DII (closer to 4MP from a 5D) versus an 18MP image from the 7D
Click to expand...
8 MP probably comes to something like 3,500x2,300 pixels. 18 MP is approximately 5,200x3,500 pixels. So, for a 12"x8" print, that becomes approximately 300 DPI for the 8 MP image and 430 DPI for the 18 MP image - the 8 MP image is certainly good enough that you wouldn't notice the extra pixels from the 18 MP image. BUT, if you had to crop to the 18 MP image to 50% to see the subject, the 12x8 print from 8 MP image drops to 75 DPI and the one from the 18 MP image drops to 110 DPI - both on the low side, and I'm not sure you'd see the difference between 75 and 110 DPI.

But lets view it the other way: if your target is 300 DPI in the final image, the biggest you can print with the 8 MP crop is 12"x8", whereas the 18 MP would let you go to 17x11 for the same DPI.

Of course, the above assumes that a pixel is a pixel, and that the lens is not the limiting factor.

--
Jeff Peterman

Any insults, implied anger, bad grammar and bad spelling, are entirely unintentionalal. Sorry.
http://www.pbase.com/jeffp25
http://www.jeffp25.smugmug.com

 
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