How To Figure Out Subject Distance To Camera For Infinity?

[LFLarry]

I am getting ready to go on an outing with my family where we will be riding on an open air tram and there will be various wildlife that we get to see. I assume the wildlife will be at various different distances from me and my camera and it got me wondering how I could use my speed graphic in a quick way without having to focus. I thought it would be a lot of fun to have the speed graphic with me for this and everyone will probably think I am crazy which could be some fun within itself.

My first thought is that I just set the 150mm lens to infinity and then ensure the animals are far enough away to make sure they are sharp enough.

The only thing is that I am not sure how to go about figuring out how far the animals need to be away from me and my camera with the 150mm lens to be in focus.

Does anyone have a guideline that you can share that is simple and easy to understand without using complicated math and theories?

Any help is appreciated.

Larry

[BrianShaw]

Doesn’t your camera have focusing scales on the bed? That’s the fast way: estimate subject distance, set focus using the bed scale, and shoot.

Describe your camera configuration more. Is your camera (rangefinder and focus scales) configured for that lens? I’m really thinking that your planning to use the wrong camera in this application.

[LFLarry]

Hi Brian, I am away from the camera at the moment, but I can check those things when I get home.

You say that "I'm really thinking that you are planning to use the wrong camera in this application". I understand that any 4x5 is not ideal for this type of scenario and that is exactly why I want to do it in addition to wanting the 4x5 negative for making beautiful prints in the darkroom. I love doing things that other people shy away from or say is wrong, etc. I love the 4x5 format and the big negative for making prints, so I want to find a reasonable method to use this camera for this application if at all possible.

Any additional tips or guidance from the group here is always appreciated.


Thanks again.

Larry




Doesn’t your camera have focusing scales on the bed? That’s the fast way: estimate subject distance, set focus using the bed scale, and shoot.

Describe your camera configuration more. Is your camera (rangefinder and focus scales) configured for that lens? I’m really thinking that your planning to use the wrong camera in this application.

[Jim Jones]

A simple and easy-to-understand way is to set the camera to a hyperfocal distance scale, use high speed film, and stop the lens well down. Unfortunately, hyperfocal distance works best for distant subjects. Brian's above suggestion is more practical. Photographers experienced with top rangefinder Graphics can probably capture good photos of wildlife from a moving tram if the wildlife isn't too wild. If I was forced to tackle this job, I'd conceal an automatic digital camera inside a junk Graphic.

[peter brooks]

If you're in bright light (outside) and can use a reasonably fast film (400) then how about using hyperfocal focussing? If you can get away with the shutter speed to use f22 (might be tricky) then everything should be acceptably sharp from pretty near to infinity.

For instance, using the depth of field calculator at DOFMaster (https://www.dofmaster.com/dofjs.html) - for 5x4, with a 150mm lens at f22, if you focus at 33.1ft then the depth of field is from 16.55ft to infinity. Depending on the animals I doubt if you would want them any closer than that!

Or tune the hyperfocal distancing to the minimum distance that you think the animals will be away from you, then you may be able to use a larger aperture and thus a faster shutter speed.

(This will doubtless start a debate about using hyperfocal calculations, what is acceptable sharpness etc. It is probably the most useful solution to your fun scenario though :))

[peter brooks]

Ah, Jim got there first...

[Alan Klein]

In addition to the above, could you prefocus at home to a specific distance and mark that point on the camera's bed? When you get to the zoo, just move the focus to that point and shoot away.

[grat]

http://dofsimulator.net

[Luis-F-S]

Doesn’t your camera have focusing scales on the bed? That’s the fast way: estimate subject distance, set focus using the bed scale, and shoot.

If not that’s what masking tape and pens are for!

[Jim Jones]

Some Depth-of-Field charts and scales on lenses are, in my opinion, too optimistic. One should check them against one's own photographs or wrestle with formulas for a reliable understanding of them before relying on them for critical work. For determining the hyperfocal distance in the field without them, estimate the diameter of the diaphram while looking through the front of the lens and multiply it by maybe 1000 or 2000. If you want a good understanding of focusing a camera and hyperocal charts and scales. Harold Merkingler has written extensively on the subject: http://www.trenholm.org/hmmerk/. Keep in mind, an obsession with such technical details can be a terrible obstacle to making good photographs.

[Kiwi7475]

http://dofsimulator.net

That is actually a very nice tool to visualize it.

[Alan Klein]

Often, I'll calculate the DOF based on some chart or the lens, and then add a stop on my aperture for good measure. Just in case I figured wrong or placed the focal point at the wrong distance from where it should be for the calculated aperture.

[peter brooks]

Keep in mind, an obsession with such technical details can be a terrible obstacle to making good photographs.

Well said. A few years back I made a 5x7 box camera with a fixed 90mm lens. At f22 it has a huge depth of field, and it is really refreshing to just concentrate on the scene and not be able to faff around with all sorts of settings.

Many popular 35mm cameras had markings for 'zone focussing', usually near (for shots of people) and far (for landscapes). My Retina IIa (with a great Xenon lens) has these two markings, at f8 they give depth of field (the manual says) from 7ft to 15ft, and 12ft to infinity. If one hyperfocal (with a small aperture) doesn't work for you then you could do a similar thing with two dof's, marking the two points on the bed with tape. Just remember that racked out is closer, racked in is far away!

Of course you may already have gone on your trip - would be great to see the results! :)

[Tin Can]

That's a great link Jim

Studio is becoming my world as my sight lessens

Thank you




Some Depth-of-Field charts and scales on lenses are, in my opinion, too optimistic. One should check them against one's own photographs or wrestle with formulas for a reliable understanding of them before relying on them for critical work. For determining the hyperfocal distance in the field without them, estimate the diameter of the diaphram while looking through the front of the lens and multiply it by maybe 1000 or 2000. If you want a good understanding of focusing a camera and hyperocal charts and scales. Harold Merkingler has written extensively on the subject: http://www.trenholm.org/hmmerk/. Keep in mind, an obsession with such technical details can be a terrible obstacle to making good photographs.

[cjbecker]

I know you say you dont want to focus, but does your speed have a rangefinder? I dont see a reason not to use it. Ive been shooting a lot of handheld crown/speed shots and its a quick camera to use. Use the rangefinder, focus, frame with the wire finder. Already have all your settings decided before you start the focusing process.

[Drew Bedo]

Isn't it the Rule-Of-Thumb that infinity focus can be taken to be ten times focal length measured from the lens to the subject?

Someone here will come up with a formula I'll bet.