Help with lens choice for extreme close up on 8X10

I want to do some 1:1 or greater close ups with my 8X10 camera and I want as much depth of field as I can get (I want my 3D subjects to have as much in focus as I can get - I don't care about the background being in focus).

I have two lenses that I am considering, both have a minimum aperture of f/45 - a 150mm Konica Hexanon GRII and a Calter II-N 115mm. Both will cover, or almost cover 8X10 at infinity.

I guess my question is pretty basic - at 1:1 will the 115mm lens offer more depth of field than the 150mm lens when both are stopped down to f/45?

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Originally Posted by Randy

Both will cover, or almost cover 8X10 at infinity.

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Hi Randy,

The image circle at 1:1 reproduction ratio is twice the diameter of the ic when focused at infinity.
So either lens will more than cover 8x10 for your application.

Quote:

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Originally Posted by Randy

I guess my question is pretty basic - at 1:1 will the 115mm lens offer more depth of field than the 150mm lens when both are stopped down to f/45?

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Depth of field varies inversely with focal length.

The shorter the focal length the greater the depth of field at any given aperture.

HTH

- Leigh

Thanks Leigh, that's what I was unsure of - the depth of field.

Yes, but the shorter the lens the greater the foreshortening. This means that those parts of the subject closer to the lens will be much larger then those further from the lens. So, if you need to preserve the shape of the subject that shorter lens will not do that. In other words, a round object will reproduce more like a football.

I think I can live with that Bob. I guess I could try 1:1 with my 250mm lens - it stops down to f/45 also but that may not give me enough depth of field on that lens. I don't think I'll have enough bellows to shot 1:1 with a lens longer than 250mm. I have about 22" of rail length.

Perhaps some of our experts can suggest an enlarging lens that easily fits into a shutter.
In my outdated experience they are the only lenses that really work for macro with 8x10.

I look forward to their suggestions.

Best of luck,
Jac

At the same magnification and relative aperture and desired image quality (that's what the dread circle of confusion is about) all lenses give the same depth of field. At the same magnification, a longer lens requires more extension but gives greater working distance. That's all you have to play with, Randy.

Leigh's statements

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Depth of field varies inversely with focal length.

The shorter the focal length the greater the depth of field at any given aperture.

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are dead wrong. Leigh, before you vanished you and I sometimes breathed fire on each other. Please check what I posted and note that I quoted you exactly before breathing fire on me.

Randy, the longest lens that will give 1:1 at 22" extension is slightly shorter than 5.5". This because at 1:1 the film plane-to-subject distance is (4 * focal length) + the lens' internodal distance. For most of the lenses we use in LF, internodal distances are a small fraction of focal length so we usually ignore them when thinking about macro work, extension and all that.

The 150/9 Konica Hexanon GR II seems to be a symmetrical lens. I sold mine years ago so can't check. It was very good at all distances. But and however, as far as I know the cells aren't direct fits in any standard shutter. As I've pointed out, Randy, until you get more than 22" of extension it won't give you 1:1.

Thanks Dan - I wrestled with my question when making this post because I thought logically that, as you state -

Quote:

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At the same magnification and relative aperture and desired image quality...all lenses give the same depth of field.

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And I don't know why I thought that a bellows extension of double the F/L would give me 1:1. So it looks like if I want to get 1:1 I have to use the 115mm.

Jac, I don't have to have an enlarging lens mount in shutter as I have a Packard shutter mounted inside the front standard. I have a couple enlarging lenses but they all have a minimum aperture of f/32. I would guess I would need f/45 or f/64 to get the depth of field I want.

Randy, I had a mental lapse. And I'm not going to hide it by editing post #7 above.

You're right, at 1:1 extension is twice focal length. You have plenty of bellows to shoot at 1:1 with your 150/9 GRII. You still have to solve the shutter problem, though.

Thanks Dan - as for the shutter - Packard is already mounted.