Shallow DOF at long range

KmH · Jun 12, 2015

Yep. Nikon D90, 500 mm, f/6.3, PoF about 100 feet IIRC:

christop · Jun 12, 2015

Applejuice said:
A 35mm f1.8 DX is something I'd consider buying at this point, mainly because it's cheap, and it's actually a 35mm on cropped sensor DSLRs. A 28mm f1.8 costs quite a bit more and will be a 42mm on the D5200, si I'll get a wider angle with the 35mm DX.

A 35mm lens is 35mm, and a 28mm lens is 28mm. DX/FX or whatever doesn't change the focal length (a DX lens generally has a smaller image circle than an FX lens, which allows it to cost less). So the 28mm f1.8 is actually wider than the 35mm f1.8 DX.

Vtec44 · Jun 13, 2015

Canon 200mm f1.8

Not my image but it gets the job done

https://farm4.staticflickr.com/3298/3662887747_7ef4fd9791_z.jpg?zz=1

Alexr25 · Jun 13, 2015

Yes folks, very nice examples of restricted DOF with telephoto lenses however none of these examples show the combined shallow DOF and the perspective that a "normal" lens (50mm on 35mm format or 80mm on 60X60 format etc) gives. To anyone familiar with photography those posted examples scream out "telephoto lens". The example the OP provided looks like it was taken with a normal lens from a few feet away rather than with a telephoto lens from a few hundred yards away. This effect can only be reproduced with a large format camera. You can throw a telephoto lens on a small format camera and replicate the DOF but then your perspective will be wrong or you and use a normal lens and replicate the perspective but you DOF will be too great but you can't do both without going to large format.

Braineack · Jun 13, 2015

100mm and f/8.0

Erin at the Rotunda by The Braineack, on Flickr

distance helps:

UVA Rotunda by The Braineack, on Flickr

but the OPs image inst so compressed like my 100mm shot.

you could say this is similar, this is 50mm and 3.2:

DSC_1724-28 by The Braineack, on Flickr

the BG isn't as deep as OOF as the OP's shot but the subject is about right in frame and shows you how fast the BG can drop OOF. This is why I suggest the OP can do something similar will any of his current lens. The Brainier method, as suggested would be the best way.

TCampbell · Jun 14, 2015

Alexr25 said:
Yes folks, very nice examples of restricted DOF with telephoto lenses however none of these examples show the combined shallow DOF and the perspective that a "normal" lens (50mm on 35mm format or 80mm on 60X60 format etc) gives. To anyone familiar with photography those posted examples scream out "telephoto lens". The example the OP provided looks like it was taken with a normal lens from a few feet away rather than with a telephoto lens from a few hundred yards away. This effect can only be reproduced with a large format camera. You can throw a telephoto lens on a small format camera and replicate the DOF but then your perspective will be wrong or you and use a normal lens and replicate the perspective but you DOF will be too great but you can't do both without going to large format.

Not "only" using a larger format camera... you can use math to find comparable lenses. The crop factor difference of a medium format (6x6cm) camera vs. a full-frame (24x36mm) camera is very close to 2. A full-frame DSLR has a 43mm diagonal. A medium-format has an 85mm diagonal. Shooting an 80mm lens at f/2.8 on a medium-format camera would provide a similar DoF to shooting with the same focal length on a full-frame camera... but at f/1.4.

I'll provide a link to an example (NOTE: Not my photo. I did a quick search on Pixel-Peeper.com to find a shot taken with an 85mm f/1.2 lens on a full-frame camera.): Buckman Flair Promo Flickr - Photo Sharing

The point is... if you find the diagonal measure of the sensor (or film) and then find the scaling factor of a one vs. the other (e.g. in my case full-frame or 35mm vs. medium-format) then you can apply that SAME factor to the focal ratio and you'll have the same DoF.

This example doesn't work so perfectly because it was taken at 85mm and f/1.2 and I would have preferred 80mm and f/1.4... there's a half-stop worth of difference.

Anyway, you can skim through this list of shots taken with a Canon 85mm f/1.2 lens: Full-size sample photos from Canon 85mm F 1.2
Or this list taken with a Nikon 85mm f/1.4 lens: Full-size sample photos from Nikon 85mm F 1.4

These will be representative of what you could get with a medium format (6x6cm) 85mm f/2.8 lens. I picked 85mm because I knew it was easy to find 85mm for a full-frame DSLR with an f/1.4 or better focal ratio. For a medium format camera, 80mm would be the more common "normal" focal length lens. But the comparison will be close enough to illustrate the point.

Derrel · Jun 14, 2015

It's apparent that there are still people who don't seem to grasp what the OP was actually about.

Applejuice · Jun 15, 2015

Well, I am learning here, so that's nice

I'm also seeing new images that tickle my fancy (like that Buckman Flair Promo shot). I guess you can say I'm a sucker for getting the subject in focus in his/her entirety, while the rest is out of focus (without looking too compressed, because that's what I'm disliking about my shots with my 300mm).

TCampbell · Jun 15, 2015

Derrel said:
It's apparent that there are still people who don't seem to grasp what the OP was actually about.

It's difficult to represent (perfectly) the example that the OP provided without using similar equipment. I think you can do this with a full-frame DSLR but not with an APS-C DSLR.

A 4x5 view camera has a diagonal measure of about 162mm -- this is approximately a 4:1 ratio vs. a full-frame DSLR (43mm x 4 = 172mm so it's not exact, but not too far off.) A "normal" 1x magnification image is presented anytime the focal length of the lens matches the diagonal measure of the recording medium. In other words... since the film has a 162mm diagonal measure then a lens with approximately 162mm of focal length would do this.

You could use a 40mm lens to get a similar angle of view with a full-frame camera (or a 28mm lens with an APS-C camera). But since there's a 4:1 ratio when comparing a 4x5 camera to a full-frame DSLR, you'd need to divide the focal length of the view camera by 4. e.g. if the view camera was using f/8 then the full-frame DSLR would need to use f/2. Canon and Nikon don't have 40mm lenses with an f/2 focal ratio but they do have 50mm lenses that go down to f/1.4 or even f/1.2. This means the angle of view would be just *slightly* more narrow (but close enough) but you would be able to get the same DOF. BUT this assumes a "full frame" camera and the OP doesn't have a full-frame camera.

An APS-C DSLR has a difference of about 6.5:1 vs. the 4x5 camera. So f/8 would need to become 1.23 (f/1.2) with a 28mm lens (Good luck finding one of those. Canon and Nikon don't have anything lower than f/1.8 in their 28mm lens offerings. But if you could find one, it would provide a similar depth of field.)

A quick check of DOFmaster and entering the values for a 4x5" camera with a 160mm lens, f/8, and a focusing distance of about 20' (wild guess and maybe that's too close) gives a DOF of just slightly less than 8' (if I increase it to 25' distance then the DOF increases to about 12').

While it's possible to re-create this shot using a full-frame DSLR, it may not be possible to re-create it with an APS-C camera -- no so much that it couldn't be done, but more of an issue with the lens & focal length required... nobody makes a 28mm lens (or anything close to it) that can provide an f/1.2 focal ratio. You could use the 28mm f/1.8 lens (at f/1.8). It wouldn't be quite a shallow and the intensity of the blur would be somewhat diminished. The OP should rent a 28mm f/1.8 prime and decide if they like what it can do. It'll be as close as they can get without switching to a full-frame body and a 50mm f/1.4 (or f/1.2) lens.

I should caution that there's a little round-off error in all of this. If I switch to a full-frame DSLR with a 40mm at f/2 and the same 20' focus distance it works out to nearly 10' (which is about what I get with the 4x5 camera if I change the focus distance to 22' instead of 20' -- my rounding off all the ratios makes this all slightly imprecise.)

The point is... you can find the scaling factor difference for the sensor diagonals and then do some math to identify what sort of lens and f-stop would be needed to reproduce the DOF on a different camera.