Questions about Macro with non-macro lens

[StoneNYC]

So last night I was shooting a model, and using my Toyo45a and my Schneider 150mm f/5.6 Symmar-S.

I was trying to take a photo of the models eye, but was having trouble focussing past 1:1 it was as if once I got past the 1:1 ratio, I just could not find any kind of focus spot, however the Bellows would extend farther than 1:1, I still was not able to actually focus it would get almost into focus but then be out of focus and no matter how fine I would turn it there was just no actual point at which it was in focus and I was forced to pull the camera back to get the image.

I understand that non macro lenses don't have quite as much detail in a macro type image because of the way the elements lineup, however to my understanding you could still in theory use the lens if you could get the proper bellows extension, so why was I having such trouble?

This was about as close as I could get, it's on an old Polaroid blue film, and is the 3x4 size not 45 size Polaroid.



Thanks for any info.

[Bob Salomon]

What magnification ratio did you want? To reach 2:1 you would need twice as much extension as you had at 1:1. Do you have that much extension available?

[StoneNYC]

What magnification ratio did you want? To reach 2:1 you would need twice as much extension as you had at 1:1. Do you have that much extension available?

If I had the extension I would certainly shoot 2:1, but no I don't have that much, however it did seem that I was not fully extended but that any closer than this and the focus became a very "soft focus" even at full extension, so I had to pull back.

So I was wondering if there were optical limitations in the lens.

[mdarnton]

In macro work always set the distance with the front standard, then focus using only the back. If you try to focus with the front you are constantly changing the reproduction ratio, not the focus. At normal distances it doesn't matter, but close up it does.

With the Toyo, try moving the model, instead.

This is one reason why view cameras in the studio. It's not a lens issue.

[Maris Rusis]

A front focussing camera is difficult to use for close-up work.

The problem is that when you rack the front standard forward the lens to subject distance changes, the repro ratio changes, and the required bellows extension changes...all simultaneously. Often it is impossible to find a sharp image at any point in the focus travel.

Work-arounds include focussing with the back of the camera, if your camera has that facility, or setting a particular repro ratio (and associated bellows extension) and focussing by moving the entire camera as a unit back and forth while watching the ground glass. This is not so easy unless you have a nice mobile studio stand or a wheeled dolly under your tripod. And finally you can tell your subject to move backward and forward until they look sharp on the ground glass, call "hold it!", and shoot.

[Bob Salomon]

If I had the extension I would certainly shoot 2:1, but no I don't have that much, however it did seem that I was not fully extended but that any closer than this and the focus became a very "soft focus" even at full extension, so I had to pull back.

So I was wondering if there were optical limitations in the lens.

Your lens is optimized for 1:20 which means that its best performance range will be from infinity to 1:10. A macro lens will give superior results closer then that. An exception would be the Apo Sironar-S which is corrected for 1:10 which would bring you to 1:5. Still not an optimal lens for 1:1 or greater.

You still have not indicated how much more extension you have beyond 1:1. Since you need to double the extension to reach 2:1 a little more extension beyond 1:1 is not going to result in much more magnification.

Also, optimal aperture with your lens is f22. What aperture were you using?

[jnantz]

try a different/ shorter lens and stop way down.
you are probably going to need a ton of light.
enlarging lenses can sometimes work as
macro lenses, if you cant get a new lens a diopters might
help .. (there was a guy on ebay that sold
some and they were large diameter and cheap )...

[jcoldslabs]

In macro work always set the distance with the front standard, then focus using only the back. If you try to focus with the front you are constantly changing the reproduction ratio, not the focus.

^ This.

I have shot with plenty of non-macro lenses for macro work and they can perform just fine relatively speaking, but having rear focus is a blessing. With the 45A you might want to set the camera within range of what you want to be in focus and use the rear sliding extension to focus, albeit crudely. The Toyo's bellows extension maxes out at around 13", so with a 6" (150mm) lens you will get just about 1:1, not much more.

Jonathan

EDIT: Another option is to set the camera at max. ext. and then have the model inch closer and closer to the lens until her eye is in focus.

[tgtaylor]

http://www.toyoview.com/Products/Acc...s/45AIIac.html See the formula at the bottom of the page.

Thomas

[Dan Fromm]

To expand a little on the point made by mdarnton and maris rusis, for all film-to-subject distances except 4f + i, where f is the lens' length and i is the lens' internodal distance, there are two magnifications (1:n and n:1) at which the subject will be in focus. In normal photography this doesn't matter -- with a distant subject this isn't a problem -- but in close-up work it can be a killer. This is why focusing by changing extension with the film-to-subject distance fixed is so problematic close-up.

When the film-to-subject distance is 4f + i the magnification is 1:1. At all other magnifications the film-to-subject distance is greater than 4f + 1. Set up the camera and subject so that the film-to-subject distance is less than 4f + i and getting the subject in focus by changing extension with the film-to-subject distance fixed will be impossible.

This is why most photographers who work at near distances set up the camera-lens assembly to give the desired magnification and then move it or the subject to position the plane of best focus as desired.