Maximum distance Z 600mm for small bird

If you would like to post, you'll need to register. Note that if you have a BCG store account, you'll need a new, separate account here (we keep the two sites separate for security purposes).

M

marvf

New member
Supporting Member
Marketplace
Member's gallery
I know that Steve has mentioned a few times (but I can't locate just where now) that he tries to keep his bird subjects at least a certain size in the viewfinder (2/3?) to avoid cropping if he can. So I'm wondering whether anyone has done the math to determine the maximum subject-to-camera distance that one should aim for when photographing a small bird, say robin-size, with a Z 600mm 6.3?

For example: here I am creeping with my Z8+Z600mm 6.3 towards a rare small bird perched in a tree. I'm a long way away, and the bird only subtends a small vertical or horizontal angle in the view finder. I know I can switch to DX mode to increase the angle subtended in the viewfinder, but that will cut my pixels down to a 20MP crop. So I take the shot for insurance, and then continue creeping towards the bird. Realistically, how close do I need to creep i.e., how large should I try to make the bird in the viewfinder to get a good full-frame shot? Obviously it's a function of the lens focal length, and I have the 600 with no TC. I can't afford the cost or the weight of the 800, so if I get the 600, I would like to have some idea of just how far away I can get reasonably "good" (I know, "good" is subjective) shots of smaller birds and take advantage of the Z8's 45MP to make some large (20x30 or bigger) prints. I understand of course that, with bigger birds, I don't have to get as close, but using the size of a smaller bird gives me a worst-case boundary for utilizing my Z8's full resolution with the 600mm.

Thanks in advance. I tried a search on this question, posed in several different ways, and came up dry.
Marv
 
Member's gallery
As you mentioned, getting the bird in the frame at a proper size is key. For songbirds, if I can, I try to get them at least one-quarter of the frame. But there are other factors in play: Are you trying to get a portrait or environmental shot? Are birds in the area more habituated to people or less so? Is the bird in flight or perched? Are there birds or other critters close by? Is it windy or wet? All these things, and more, will have impact on bird behavior and how close you can get.

If distance is something you need to know, put a bird sized stuffed toy on a perch of some kind. Take photos of it at various sizes in the frame using your 600 PF and measure your distance with each shot.

I hope this is helpful.
 
Member's gallery
marvf said:
So I'm wondering whether anyone has done the math to determine the maximum subject-to-camera distance that one should aim for when photographing a small bird, say robin-size, with a Z 600mm 6.3?
Click to expand...

FWIW in the lockdowns I sometimes used to shoot from my back bedroom window into my garden with my Sigma 150-500 Sport and found that small birds like our UK Blue Tits at a range of about 35 feet were very small in the frame. A 1.4x TC made little difference and better was with the lens and TC on my Fuji XT-4 which gave the equivalent of 1260mm.

These birds are very small at about 5 inches from tip to tail.
 
Member's gallery
as already pointed out, it depends a lot on the image you want to take .If you want to show a bird in its environment, then maybe a very small bird will do.
I try to fill at least 25% of the width of the frame with the bird if I want it to be large in the frame. I have a Z8, so that allows for some more cropping than a Z6 III, for example.

One thing to keep in mind is heat haze (heat refraction). When a bird is too far away, it's not only the reduced number of pixels that can reduce sharpness but in certain situations heat waves in the air can also reduce sharpness. The further away a bird, the more this will come into effect.
With a lot of heat refraction, even one of the premium 4/600 lenses will not yield anything that one would call sharp.

Here is a great video by Steve about this:
 
Here is a good free one. You can set whatever crop factor you want. So 600 mm lens with full frame with a 6 inch tall field of view would be about 13 feet away. Crop to 1.5 and it would be about 19 feet.

Camera Field of View Details and Calculator (FoV)

Calculator of Field of View of camera and lens, both the dimensional size of the Field Of View seen at a specified distance, and also Angle Of View.
www.scantips.com
 
Last edited:
Member's gallery
Simple formula, take the size of the subject and divide by the tangent of the angle of view of the lens. Answer (distance from the lens to the subject) will be in whatever units you used for the size of the subject.
 
Another way to approach this is to walk around with a mental image of how a common object would fit. For example with a 600mm lens on a full frame camera a 12 inch ruler would fit the diagonal of the frame at around 14 feet. Knowing that, you know that half a foot would fit at around 7 feet, 2 rulers would fit around 28 feet, and so on. So in the field you don't need a calculator, just imagine someone holding a ruler up at different distances.
 
Member's gallery
Thanks to all of you who replied. I've just ordered my z600 mm lens and will begin experimenting. I have been using the 500 mm PF with my D500, but since that's been replaced with a Z8 now, I decided to go for the Z600 rather than the Z800 since at 80 years old, I think for me the lighter lens will be a more enjoyable experience.
I have noted with interest the discussions about atmospheric conditions playing a big part in the overall sharpness of photographic images taken at very long distances and therefore have decided to restrict myself to birds and wildlife that can comfortably be photographed adequately with a 600.
And BTW, my pristine 500mm pf will shortly be posted here at BCG for sale.
Marv
 
The factors for field of view are sensor size, focal length, and subject distance. So the 600mm with full frame will surprise you that it will have just a little more reach than the 500mm d500.
 
Member's gallery
Thank you, Bill. I do understand the difference between comparing a DX crop 500 mm with a full frame 600 mm. And the nice thing about the Z8 is that you have the option to go to the DX crop on the Z8 if you need it. I'm going to try to capture some birds using the full frame with the 600 so that I can print large. I also think there's a lot of opportunity at a zoo capturing facial expressions of some of the larger animals such as gorillas and chimps, that can manipulate their face. I think it would be cool to have a 20x30 of a chimp making a dramatic face (remember the shot of Einstein with his tongue sticking out?).
 
You must log in or register to reply here.
Back
Top