Sigma 90 mm f 2.8 Af Macro

I love macro lenses and have tried a lot of them. When I saw an used but  good  sample of the old Sigma 90 mm f 2.8 Af macro , at a bargain price, I could not resist to buy and give it a try. Having owned it successor (105 macro EX) for a while, I was curious about differences and image quality.

The 90 sigma is a small lens, slightly smaller than the 60 micro nikkor.

It comes with an hood which nearly doubles its length

It has a narrow focusing ring, quite like the first AF Nikkors. It is not comfortable, but neither  loose, so that manual focusing can be precise enough for critical macro work. The barrel is made of metal and feels solid.  a large rubber ring helps to hold the lens while putting on/off the camera. As most short tele macros of its generation, it reaches 1:2 instead of 1:1 (on full format). However,  it was sold in bundle with an 3+ achromatic two elements diopter, of very good quality  which allows  to reach 1:1.  F/stops go from 2.8 to 22. AF is moderately slow and quite noisy. A good thing of this lens is that it extends very little (2cm) at minimum focusing distance,  while the new 90 mm Tamron or the Sigma 105mm EX nearly double their lengths (but they reach 1:1 without adds-on). Wide open the 90 seems a bit softer than the 105 Ex but at f8-11 results are virually indistigushable to my eyes.

Here are some technical data (within brackets those for the 105 EX for comparison)

lenses/groups 9/9 (10/9),  minimum focusing distance/reproduction ratio on full format: 32 cm /1:2 - with diopter 22cm/1:1 (31 cm /1:1).

And  what about image quality?

Here are some samples:

Each flower is less about 1cm wide

Ammonite - 4 cm wide

Baboon skull ...Hey, I'm a vertebrate palaeontologist, and thus my sample pictures sometimes  may seem  a little odd  ;-)

My usual test subjects, two little fossil fishes from Green River ( the complete one is about 4 cm long)

Here below  at minimum focusing distance on D70

 (1/320s f11 with  flash, no postprocessing)

and a 100%crop of the original picture

As written above, the 90 Sigma Macro was sold with a +3 achromatic close up lens of very good quality which allowed to reach 1:1 on full format (1.5:1 on D70)

At minimum focusing distance on D70 with the achromat (same settings as above):

and the 100% crop of the original picture:

It is possible to detect  the cracks in the opercular bone!!

In conclusion, I think that the Sigma 90 2.8 Af Macro is a very good lens,  it has some obvious (age related) limitations with respect to  105 Nikkor and Sigma or 90 Tamron, mainly the 1:2 maximum RR, (but  on APS sized slr the crop factor helps). However, in my opinion, for  the price it is sold now,  it represents an  excellent option for anyone on a tight budget, being definitely better than some low-end 105 macro f 3.5 still on sale ...

(And the close up achromat is really that good ,and works weel also on other lenses) .