Focus-Throw and Aperture Question on the Sigma 180mm APO Macro

[KarlMera]

Although the lens is f/2.8, this will not be very usable except at infinity, although the lens is designed for macro work. This is due to what is called “effective aperture.” As with many lenses, the moment we focus close with the Sigma, the actual aperture jumps to f/4, not helpful for the best bokeh. I like f/2.8 or preferably better, like f/2 or f/1.2.

For macro I only know the Repro-Nikkor 1/85mm that has an effective aperture of 2 at 1:1.

[Michael Erlewine]

For macro I only know the Repro-Nikkor 1/85mm that has an effective aperture of 2 at 1:1.

Well, I don't do much 1:1 macro work, but rather close-up photos, so let's broaden that a bit, then, and say "better than f/2. and also include lenses for close-up work, which (in my work) includes the CRT-Nikkor, the Repro, the CV-125, various f/1.4s, and soon (for me) I will see what I can do (close-up) with the Noct Nikkor.

We each have our priorities for what we feel we need in a close-up/macro lens. I am just using my own in this.

[KarlMera]

Well, I don't do much 1:1 macro work, but rather close-up photos, so let's broaden that a bit, then, and say "better than f/2. and also include lenses for close-up work, which (in my work) includes the CRT-Nikkor, the Repro, the CV-125, various f/1.4s, and soon (for me) I will see what I can do (close-up) with the Noct Nikkor.

We each have our priorities for what we feel we need in a close-up/macro lens. I am just using my own in this.

All these lenses have the engraved apertures only at infinity. The CRt-Nikkor has the effective aperture of 1,6 for example, not 1,2.

[KarlMera]

The Noct Nikkor would have about 1,8 with a small extension ring.

[Michael Erlewine]

Thanks Karlmera for the details.

[KarlMera]

The 180 Sigma has its best resolution at 4-5,6, but it ist too big and heavy, I would recommend instead an apo-sironar digital 1:5,6/135 and use it open with 5,6 for your work.

[Michael Erlewine]

The 180 Sigma has its best resolution at 4-5,6, but it ist too big and heavy, I would recommend instead an apo-sironar digital 1:5,6/135 and use it open with 5,6 for your work.

Can you tell me something about the APO Sironar and its qualities?

Is this one:

http://www.ebay.com/itm/Rodenstock-135mm-f5-6-Apo-Sironar-N-MC-Copal-0-/171987482098?hash=item280b40b5f2:g:RaYAAOSwlaxWOB6j
 

[KarlMera]

Can you tell me something about the APO Sironar and its qualities?

Is this one:

http://www.ebay.com/itm/Rodenstock-135mm-f5-6-Apo-Sironar-N-MC-Copal-0-/171987482098?hash=item280b40b5f2:g:RaYAAOSwlaxWOB6j

It should be the digital version, it is computed for smaller image circle. I have tested the Sigma, but the apo sironar digital is much better, also more expensive than the old sironar.

[Michael Erlewine]

It should be the digital version, it is computed for smaller image circle. I have tested the Sigma, but the apo sironar digital is much better, also more expensive than the old sironar.

I see the difference. So I could get a copy, get the Novoflex adapter for Copal-0 which fits my Rollei X-ACT 2 bellows and that would work well, correct.

The setup is here:

http://nikongear.net/revival/index.php/topic,2709.0.html

[KarlMera]

I see the difference. So I could get a copy, get the Novoflex adapter for Copal-0 which fits my Rollei X-ACT 2 bellows and that would work well, correct.

The setup is here:

http://nikongear.net/revival/index.php/topic,2709.0.html

Yes, if the bellows is long enough that you can reach 1:3.

[Roland Vink]

So, for example if you have a 100mm and 200mm macro lens, both with 300 deg focus throw, both get to 1:2 at close range - if you shoot the same subject at the same magnification (working distance is obviously different), then the focus throw to cover the subject will be similar (I think?)

I knew this was wrong... If for example, you focus the 100mm from 1 - 0.5m, and the 200mm from 2-1m, the focus throw will be the same over this distance (focal length and distances doubled, but magnification is the same). However, the 200m lens covers twice the distance (1m from 2-1m) compared to the 100mm lens (0.5m from 1-0.5m), so it focuses twice as fast for the same focus rotation. If you want to focus-stack a flower with 5cm depth inside that range, the 200mm lens will require half the focus throw compared to the 100mm lens.

So, if you need very slow, precise focusing, in general a shorter lens will give you greater control than a longer lens. On the other hand, the longer lens, with the narrower field of view, will give you more blurred backgrounds for the same DOF (or you can stop down more for greater DOF on the subject, with similar amount of background blurring as the shorter lens)

[ch96066]

Just got my hands on the 180 OS. Goal is to compare it with the 150 non OS, which is my current favourite macro.
Regarding the f-stop it is 2.8 only up to 3 meters. Then it gradually stops down to f5, not only f4. I think the 150 goes to 5.6 but i will double check.