TAMRON SP 90MM MACRO F2.5
Personally - if I am buying a dedicated macro - I want 1:1, but there are other cheaper ways including tubes and reversing rings and many get good results with these.
You could also try a macro adapter such as the excellent Raynox DCR 250 which will cost you less than £50. These are by far the easiest of the alternatives as they just clip on to the front of any lens with a thread of up to 67mm and can produce great results
Carl
No matter how many lenses I have owned - I have always needed just one more
I like the colours the lens produces, it seems particularly suited to autumn's warm colours. It is very sharp.
You should be aware that the lens can produce a purple spot in certain conditions, I have seen it with my lens on occasion. See here.
SRS have one in mint condition with the adaptor for what looks like a reasonable price, you can get the postage free as a forum member. It hasn't got the extension tube but I'd happily sell you that.
I have considered selling mine, but prices have come down. I have a 1:1 macro and a 1:2 is still useful. Every now and again I like to have a session with it to remind myself how good it is. I actually think I might prefer it to the Pentax DFA 100 and I have wondered whether to change from the Pentax to a 1:1 Tamron. Anyway, enough of a rabbit, here are some piccies taken with the Tammy:





You can see some of my photos here if you are so inclined
It is sensor flare, a reflection from the flat surface of the rear lens element. It can show from f8, but does depend on the contrast within the image.
The good news is that if used with the matched extension tube or 2x converter, the flare is eliminated.
Ideally you also want to use the lens with an adaptall PKA adapter.
This lens is my favourite and a pure joy to use. The one caveat to this is the purple spot ( that Dr O mentions) that can appear when the lens is stopped down.
It is sensor flare, a reflection from the flat surface of the rear lens element. It can show from f8, but does depend on the contrast within the image.
I agree that the flare seems more of a problem when there is something dark at the centre of the field, and it is most of a problem at small apertures - which one tends to use for macro!
Is it reflection off the rear lens element, or off the rear of the diaphragm? I rather guessed the latter, because it gets worse at the diaphragm closes.
The good news is that if used with the matched extension tube or 2x converter, the flare is eliminated.
I didn't know that. That is good news
Ideally you also want to use the lens with an adaptall PKA adapter.
Some of the Adaptall adapters can be expensive. A plain no-features one can be had at a reasonable price, but then one has to use the lens mainly as a manual, or at best, in Av mode. No autofocus.
I still have my SP90 f/2.5 from 35mm film days, and it is certainly a very good lens. The digitally adapted model is rather expensive. I keep thinking of exchanging (but at what value???) for a Pentax 100mm macro.
Martin
A few of my photographs in flickr.
Lizars 1910 "Challenge" quarter-plate camera; and some more recent stuff.
Is it reflection off the rear lens element, or off the rear of the diaphragm? I rather guessed the latter, because it gets worse at the diaphragm closes.
The rear element and reflectivity of the sensor is the problem. It is refered to as sensor flare.
As I understand it, a sensor is more reflective than the surface of film. Light reflected from the sensor is then re reflected from the flat face of rear element back to the sensor again.
I have not experienced it, but I have heard sensor flare can be a problem with some lenses when used with a filter. Once again, the flat face causing the problems.
Python118. I think you are talking about a different lens. The op is asking about the Tamron adaptall sp90 f2.5, a vintage manual focus lens, not the current AF lens which does go to a full 1:1 macro and does not suffer sensor flare.

might just get a set of tubes for now
regards
Russell
Pete
K-1 K-01 Q-7
some len
Close to the Edge
Down by the River
Fine on the K100D, showed up on the K-7 ( where the 300/5.6 showed it much more)and the K-5 no issue
K-1 K-01 Q-7
some len
Close to the Edge
Down by the River
thegreenman
Member
I o have a 50mm 1.7 which I could use with tubes. Would this give better results?
regards