View Full Version : Nikon Macro 120mm 5.6: how good is it for non-macro?

9-Dec-2006, 05:37
I realize this lens is optomized for macro. Does that mean it's no good for distance shots, even at f22?

It has a published coverage of 250mm at f/22 and 1:1. How much less is the coverage at infinity?

Arne Croell
9-Dec-2006, 05:58
I realize this lens is optomized for macro. Does that mean it's no good for distance shots, even at f22?

It has a published coverage of 250mm at f/22 and 1:1. How much less is the coverage at infinity?

Since I haven't used one, I can't answer the 1st question, but the answer for the second question is easy: 125mm at infinity - because at 1:1 the lens is 2 focal lengths away from the film, and at infinity just one focal length (disregarding any changes in performance due to the wrong correction as referred to in question 1). The circle of illumination might be bigger though, both at 1:1 and at infinity.

Walter Calahan
9-Dec-2006, 06:12
All macro lenses are optimized for macro work, but they can be used for general photography too. I'm sure there is some trade-off, but I'm not an expert at this subject.

Jeffrey Sipress
9-Dec-2006, 09:25
I have this lens, but also a 'normal' 120 for general landscape. I've heard that it is optimized for close work, but never saw any information to quantify exactly what would be degraded if used conventionally.

9-Dec-2006, 10:17
Jeffrey, if Arne's forumla is correct (which I think it is), then the lens would not cover 4x5 at infinity; in fact the lowest magnification at which it would cover 4x5 (assuming a 160mm diagonal) would be around 1:4, which I believe would be a distance of around 60 cm.

Have you found this to be true of you lens?

Jeffrey Sipress
9-Dec-2006, 17:20
Thanks, Rider. I haven't done any tests of that nature, but I may, now that my curiosity is sparked.

Andy Eads
9-Dec-2006, 20:43
I own one and it does not cover 4x5 nor is it very sharp at infinity. It is, however, the finest closeup lens I've ever used.

Ted Harris
10-Dec-2006, 09:02
I have never bothered to compare the performance of a macro lens at infinity v. that of a stndard plasmat, simply because the macro lens formulas usually give you a much smaller image circle and thus no reason to compare if you won both (as I do). Finally, in my case it would be a comparison of a 180 macro v. standard 180. The 180 macro nver leaves the studio, it is too large and heavy compared to the 180 Apon Sironar N to even think of toting it in the field (unless I KNOW I am going out to do maro work).

Hgaving said that if someone wants a comparison I'd be happy to burn a couple of sheets of T55. Let me know.

11-Dec-2006, 07:16
This might seem like a naive question, but why would a macro lenses have such a short focal length? I think Schneider makes 80mm, 120mm and 180mm. I went ahead and a bought a new Nikon 120mm--the price was too tempting, and who knows, one day it'll come in handy.

Ted, I would love to take you up on your offer, if it's not too much trouble.

Janko Belaj
11-Dec-2006, 07:28
I own G-Clarons, 210 and 240 mm lenses, both repro lenses - close in definition to macro lenses (optimized for 1:2 to 2:1, as I have found in literature) and have found them excellent all-purpose lenses. Haven't seen any degradation in their work for architecture or landscape. Other way - normal lenses (I have worked only with Symmar and Sironar) aren't that good at macro work. Modern Sironar (not APO!) slightly better than old Symmar, but both way below quality of G-Claron. So Rider, I believe your only problem is lens coverage...

Ernest Purdum
11-Dec-2006, 07:54
Rider, macro lenses are made in short focal lengths so as to give magnification without excessive bellows extension. Some are much shorter than the 80mm you mention. They are apt to be optimized for the subject:image ratio you would expect at an extension of 500mm or so. You need 2X focal length extension to get to 1:1. Each focall length past that gives one more even number of magnification. So, as an example, the 120mm lens at 480mm extension would give you a magnification of 3:1 and this is very roughly the area at which you could expect optimum performance, but it would no doubt perform very well over a fairly wide range of magnifications. Only the lens maker or someone with great experience with the particular lens could give you more precise information.

The tradeoff when you use particularly short focal lengths is that the lens winds up very close to the subject, making it very difficult to arrange illumination. When you use a lens of 17mm or so, it is usually only feasible to photograph items that transmit light, so you can illuminate through the subject.

Armin Seeholzer
11-Dec-2006, 08:15
I tested my 120mm APO Macro Sironar at infinity and at f 16 it was as sharp as my other general pupose lenses, but I had to stop down to f8 for focusing and it was difficult to focus at infinity.
The Rodenstock has a bit the larger image circle then the Nikkor it just covered 4x5 at infinity!

Steve Hamley
11-Dec-2006, 09:32

Two reasons: 1) at the manufacturer's intended magnifications, the bellows draw can be significant, for example, 1:1 would require twice the bellows draw of the focal length. 2) as the focal length increases, the DOF will decrease compared to a shorter focal lenght at the same distance. I macro, more DOF is better.


11-Dec-2006, 10:14

The first reason (shorter bellows draw) makes perfect sense (and I suppose that needs to be balanced against working distance).

I don't quite understand the DOF reason, since I thought DOF was determined by f-stop and magnification.