Question from the village idiot.

[donlfaulkner]

I take my 35-200mm lens and put a x2 converter on it and focus on an objec,t adjusting for a focal length of 200mm. The lens distance scale indicates 30 ft. I have my f/stop adjusted to 3.4 (wide open for this lens).

I have actually focused on an object 60ft away which gives me a DOF of 1.35ft, not quite a foot and a half, (near limit is 59.3 ft, far limit is 60.7 ft) with a focal length of 400mm. I'm shooting 35mm film.

Am I correct so far? I think I'm beginning to get a grasp of this stuff. I see that the cirlce of confusion is .03mm. That I finally understand. What I don't understand is why the Hyperfocal distance is a whopping 5203.4 ft!

I got this information from Online Depth of Field Calculator but I'm not sure I'm using it right.

[donlfaulkner]

Originally Posted by donlfaulkner

... What I don't understand is why the Hyperfocal distance is a whopping 5203.4 ft!

I got this information from Online Depth of Field Calculator but I'm not sure I'm using it right.

Can anyone shed some light on this?

[ramblinray]

Because you have the TC on the lens, the aperature is more like 6.7 I believe. That changes the results some for you.

[donlfaulkner]

Hyperfocal distance is not making sense to me.

[humminboid]

Definitely NOT an idiot!

O.K., It's been years, but If I remember correctly, at any given f/stop, hyperfocal distance is the distance from the film plane to the first object in acceptable focus, with the lens focused on infinity.

Depth of field, which is related to HFD, is the distance from the first object in acceptable focus to the last one. THIS is the important measurement!

Now, how does that relate to the real world? With your combination, It really won't very much. When a lens is focused on infinity, it actually focuses "To Infinity and Beyond", which is why the moon is in focus when the trees on the horizon are sharply in focus. HFD focusing just moves the zone of acceptable focus closer to the photog and made it more usable.

Hyperfocal distance focusing. in the dark ages, known as "zone focus" (and actually may have only a tangential relationship to "real" hyperfocal distance) and is/was used by news photogs before the magic of autofocus. They used moderate wide angle to normal lenses...35, 50 and maybe 85mm.

Remember, 28 mm was really WIDE back then! AND lenses all had distance scales marked on them.

They would pick an f/stop,say, F/11, then set the focus by lining up the distance scale mark,ohh, at 15 feet, with the f/stop mark and leave it there, adjusting for changing light conditions only as necessary.

In average conditions, shooting Tri-X, if a photo opportunity presented itself, they'd just raise the camera to their eye and shoot. Everything from less than 10 feet or so to maybe 30 feet would be in acceptable focus, depending upon f/stop used. Scenic photographers also used the principle, to insure that most of their composition was in focus.

A 200mm tele with a 2X converter=400mm, and has 2 stops slower (larger) maximum aperture than a lens without converter, and has such a narrow depth of field, HFD is a moot point. A tele compresses the elements of a photo, and it is a bit of a stretch to expect front-to-back sharpness in most cases.
Imo, with your long tele, and without focusing scales, HFD focus will be somewhat of an exercise in frustration, which seems to come through in your post.

Actually, IMO, the whole hyperfocal distance thing is best ignored, because it is not something than does more than spread confusion, hate and discontent. The DOF calculator is a very handy thing to have, like when my buddy was agonizing about why his race cars pixes are not sharp from end to end, using F/5.6 with his 300mm lens. There just isn't enough DOF!

This has gotten really long, and I hope it has not added to your confusion. If so, apologies!

[donlfaulkner]

Carl, that has cleared up a lot of my questions. It sounds like a theory that is more for argument than actual use in the field.

Ie: set the camera for the best focus (f/?, focus, shutter speed) for the scene at hand and leave theories for those that care about such things.

I do, however, miss the distance and dof markings on my digital camera...but not much.

[humminboid]

Originally Posted by donlfaulkner

I do, however, miss the distance and dof markings on my digital camera...but not much.

Glad it helped, Don.

Yeah, me too! but, digital is what it is, and they won't put the genie back in the bottle any time soon.

Not that I'd [I]ever[/I ]want to go back to the "good old days"

I'd rather enjoy the magical nature of photography, burdened with only the technical information that will help me be a better photog.

One of the old masters of photography said "The technical side of photography can be taught in an hour, (for me, probably more like 3 hours) but, the eye...takes a lifetime of development."

Just so long as we don't lose the wonder of it all, and the fun, amid the technical details and the constant struggle to be as good as we want to be..

Now go and take some more pictures...the more we shoot the better we get!