Newbe question on Macro 8X10

[eoghan]

I would appreciate any help or pointers in helping me move from 4X5 to 8X10 macro work.

Up to now I've been doing close up work on small objects (1 to 2 inches tall) with my 4x5 and have been wondering what would it take to do this with a 8x10 camera, same objects but filling the 8x10 frame.

I have been using a Rodenstock 150 on a old 4X5 Arca Swiss mono rail camera. I typically max out the bellows in order to fill the frame but it works well for what I am trying to get.

My 8X10 is a bashed up, Burke & James mono rail and a 12" old brass lens and I cant get enough bellows for close up work, the closest I can get is about 5 feet. I expect to upgrade my 8X10 camera in the next few months, looking at the Sinar F series.

I have no idea what the formula might be for calculating what how much bellows one needs for a particular format and lens combination or if its even possible with the lens I have.

Eoghan

[Frank Petronio]

You could try the 150mm lens for close-up work on the 8x10 without spending a lot of money. Even though it sounds radically wide, at that degree of close-up it won't look that way. And to get a 4 to 1 repro ratio... (8" on film from a 2" subject)... well good luck!

[r.e.]

I have no idea what the formula might be for calculating what how much bellows one needs for a particular format and lens combination or if its even possible with the lens I have.

Assuming your 150mm lens, you need 150mm of bellows for infinity, 300mm for 1:1, 450mm for 2:1, 600mm for 3:1 and 750mm to get to the 4:1 magnification you want.

For your 12 inch/300mm lens, double each of those numbers. So to get to 4:1 with this lens, you will need 5 feet of bellows.

These numbers are determined by the focal length of the lens and they hold regardless of whether you are shooting 4x5 or 8x10.

There's an article by Ernest Purdum on this site that you might find useful: http://www.largeformatphotography.info/macro.html

In addition to the question of bellows length, you need to understand the issues of working distance (i.e. distance from the lens to the subject), depth of field and exposure compensation at the kind of magnification you are talking about.

[eoghan]

Thank you both for your replay, exactly what I was hoping for.

Frank, I have been following your work for a long time, thanks again.

[Ken Lee]

Something else to consider, is the image circle. A lens which only covers 4x5 at infinity, will cover 8x10 at 1:1.

At 4 times the focal length (3:1 magnification), the circle of coverage will be 4 times larger, namely 16x20 inches.

So if you plan to shoot at 3:1, you can probably use a lens which was intended as an enlarger lens, or a macro lens for medium format film. (Just be sure to reverse the enlarger lens, because it's designed to make something small, larger. You want the subject to be small, and the film to be large)

If you shoot with an 80mm lens, then you will only need 320mm of bellows draw to reach 3:1, but the 8x10 frame will be filled.

It should be easy to find an affordable enlarger lens in that size, or better still, a real macro lens.

[Bob Salomon]

Yes, if you have enough bellows, your 150 will work at 1:1 and closer, but not nearly as well or as sharply as a macro lens will.

As an example the 120mm Apo Macro Sironar covers a 347mm circle at 1:1 and the 180mm covers a 562mm circle.

[eoghan]

Thanks again for all the good tips, this really helps.

[Milton Tierney]

This might be silly, but can a LF lens be reversed for macro? I know this has been done with small format. Just a thought.

[Dan Fromm]

This might be silly, but can a LF lens be reversed for macro? I know this has been done with small format. Just a thought.Depends on what shutter it is in. If in #1, no, otherwise I think yes. This because the #1 isn't symmetrical.

Whether the lens should be reversed depends on magnification. If > 1:1, yes, otherwise, no.