Which Canon body for image quality when cropping tightly (birds)

I photograph small birds in the backyard from a deck and it is a focal length limited scenario. I like the vantage point I have from said deck and moving around or trying to get closer would scare the birds off. I have a 7D II + 100-400 II for birds in flight. I want to use my Sigma C 150-600 (tripod mounted) as a second body combo for static shots of birds. My thoughts are that the extra focal length will put more pixels on the subject.

I would love a 600mm prime but I don't want to risk a 1st gen Canon due to age/possible failure.

I've been thinking about which body to use with the Sigma. The birds are small and at varying distances. I've been thinking and reading so much that my brain is in a fog and I would like some input please.

My main thought is: is it better to use a full frame body for the IQ or a crop body for the pixel density?

I did a test scenario with my 6D @ 600mm & 7D II @ 400mm so the resulting photos were very similar. The 6D came out sharper for fine feather detail. But I may have goofed and had my shutter speed to low on my 7D II.

The options I have are: 6D, 5D II & Sony A6000 (1.5 crop) and I'm open to other options.
With the MP difference (20-24) being so small, maybe a prime telephoto is the better answer?

It might be a push. The 6D is FF but it doesn't have the "reach" as your 7D does. This means you will have to crop even more which may lead to a loss of detail or extra noise. I went from the 7D to the 6D & love the noticeable difference especially at high ISO. The only thing I miss is the FPS.

As stated, it will be very close in comparison if you shoot the sigma at 600mm on two different formats, and then crop the FF to match and resize to the same resolution. The 7D2 pixel density provides an equivalent 1.6 TC, which is one of the reasons people keep a 7D2 in the bag.

Be sure to run the shutter speed up a bit though on the 7D2 if you are going to pixel peep. The AF on the 7D2 is quite nice for birding too, especially spot AF to target a small bird amongst the branches.

Curious how much of the frame that Sparrow took up on the original?
This topic is of interest to me.

Certainly shows nice details.

I took about half a dozen photos of this on my 7D and I think the shutter speed is ok since it was on a gimbal. I believe the lack of detail compared to the full frame is the cost of the smaller pixels. The Sigma was handheld with OS on.

On the left is the 6D/150-600, on right 7D2/100-400.
While the 6D image looks clean and great, I've got to take some time putting the Sigma 150-600 back on my 7D and see how the detail compares against what I've seen thus far. I'm sure it will be better and what I'm looking for but that means I need another crop body for the Sigma. I just don't trust the Sigma AF for birds in flight due to past experiences. Another option is to continue to use the 6D, it will be a strength with its ISO capabilities if birds are in low light. Hmm..

So I was thinking... keeping things equal.

The 6D and 7D2 have the same megapixels - 20.2,
the focal length is pretty much the same: 6D @ 600 , 7D2 @ 400*1.6 crop = 640
and I see that zooming in to 100% causes nearly identical photos.

With the 5DSR being 50 MP,
keeping the focal lengths the same: 5DSR @ 600 , 7D2 @ 400*1.6 crop = 640
zooming into 100% should be 1.6 times more "magnification" than the 7D2?

because if I'm correct,
the 5DSR @ 600 and the 7D2 @ 600
should be equal in size zoomed into 100%.

Ok now the 80D is crop @ 24 MP (4 extra MP),
thus it should be slightly larger at 100% than any mentioned above.

With the assertion that full frame comes out better in quality, would the 5DSR be better than the 80D or would it be a wash?
I'm not so sure it is worth the price difference and in a year or so we could have another megapixel jump (the next EOS R release?)

For the record, I don't put much on megapixels. I still love to use my 1D classic @ 4mp. It is simply for the ability to crop out tiny birds in the frame.

The FF sensor sees the IDENTICAL projected image from the lens as would be seen by an APS-C camera sensor, with the same FL lens on both.
So assuming that an object being photographed creates a 5mm image at the focal plane -- regardless of frame size! ...

1. the 6D has 152.8 pixels/mm, so only 764 pixels on target
   
2. the 5DS has 241.3 pixels/mm, so 1207 pxiels on target
   
3. the 7dII has 244.3 pixels/mm, so 1221 pixels on target
   
4. the 80D has 266.7 pixels/mm, so 1333 pixels on target.
   

• one photo is shot at 1/640 while the other is shot at 1/50
  
• only photo has a smaller image of the bird, while the other image is larger
  

The 5ds has about the same pixel density as the 7d2, and 100% crops are very close in nature including noise characteristics. The 5ds may render fine detail better though producing a bit better overall final result.

I would continuing using the 7d2 with the sigma, and work on adjusting micro focus, along with working on shutter speed, to see what can be captured. See if you can reach a happy compromise on final results.

At this point, using a short 600mm focal length is likely just going to always be your limiting factor because there's not a terribly big difference between the pixels of any sensor size on these Canons, 4.09um vs 4.14um is literallly insignificant in terms of how resolution is recorded and both will sample ideally with the 95mm aperture of your 600mm lens around F19~F20 if you want to get the most possible resolution recorded for your system. Obviously this poses issues and this is why everyone photographing with these systems are undersampling the data.

Instead of worrying about trying to use essentially the same pixel size, aperture and focal-ratio to maximize resolution recording on tiny birds (which would require SMALLER pixels actually) you could at least move towards something like a telescope or spotting scope with significantly longer focal lengths and larger apertures to better sample with your current camera's pixels. An example would be something like a 127mm or 150mm F11~F13 SCT or Muskatov telescope, for example: https://www.bhphotovid​eo.com …D_BwE&lsft=BI%3​A514&smp=Y

+++++++++++++++

Alternatively, since this is backyard birding, you can do yourself a huge favor and simply set up a blind. You can make a simple blind or hide and get closer to the birds. This makes a big difference. A good hide and you'll find you can shoot with a short lens. Plus with a feeder or a few, they will literally go to the same place each time, perch in common places each time and you will have an easy job where your lens is pointed at the right place most of the time and they just come to the right spot for your shot, already focused even. If you're set up in the back yard, I highly recommend a feeder and blind. They get something from it (feed) and you get closer.

My daughter and I made this blind and we do song birds at a feeder in our yard:

IMAGE LINK: https://flic.kr/p/29Ad​JQd

IMAGE LINK: https://flic.kr/p/QfuX​rf

IMAGE LINK: https://flic.kr/p/2aZA​Hzc

Why not just use a second 7d2 with the Sigma? Is there an incompatibility there I am unaware of? That would give you pixels on target and less cropping vs using it on the ff bodies.

The less cropping you have to do, the better. A 50% cropped full frame isn't going to be any better than a shot that fills the frame on a crop body. I still use a crop sensor camera when I want extra reach. For me a cropped 42 mpx image doesn't look any better than an uncropped 24 mpx image. Use you 150-600 on your 7D... it should work just fine.... in my opinion.

avondale87 wrote in post #18879931
Curious how much of the frame that Sparrow took up on the original?
This topic is of interest to me.

Certainly shows nice details.

Here is the full frame and then a crop reprocessed. The bird occupied about 12% of the frame.

TeamSpeed wrote in post #18880575
Here is the full frame and then a crop reprocessed. The bird occupied about 12% of the frame.

Hosted photo: posted by TeamSpeed in
./showthread.php?p=188​80575&i=i67683343
forum: General Photography Talk

Hosted photo: posted by TeamSpeed in
./showthread.php?p=188​80575&i=i124054748
forum: General Photography Talk

Hey TS. What do you mean by 'crop reprocessed' exactly? Sorry but it isn't immediately obvious to me what you are referring to. And did you change your avatar or are things just looking more frightening as I get older?

nqjudo wrote in post #18880588
Hey TS. What do you mean by 'crop reprocessed' exactly? Sorry but it isn't immediately obvious to me what you are referring to. And did you change your avatar or are things just looking more frightening as I get older?

That picture was from 3 years ago and I decided to reprocess the cropped version tonight once I found it in my archives. Just some contrast, saturation and smart sharpening....

Another shot of this rascal from the series, again from the 7D2 and Sigma 150-600 at 600 wide open. Settings are a bit crazy because I was in the back yard with no direct light and then walked to the front, and didn't bother to change anything.

Ah. Ok. I didn’t know if you were talking about upscaling the crop for print or something. Haven’t had much luck with that. They look good anyway. Thanks!