TAMRON SP 90MM F2.5 MACRO LENS.

hi all, lens is on its way, cheers to simon. hope to have it sometime this week, whoohoo

Thanks. I have never noticed any problem with flare.

I've also never noticed this blue flare disc, although the only time I've used this lens stopped down as far as f11 would be in macro situations, where I suppose it would be rare for the centre of the image to be very dark.

Just in case anyone is curious, I have put two examples up on my website. Very noticeable flare at f/22, none at f/2.5

Martin

Don't know if this info will be of use but you never know.


Tamron SP AF 90mm f/2.8 Macro 1:1 Di Lens for Pentax £248.99 Brand new www.onestop-digital.com/index.php I purchased one in Jan of this year, I think P&P came to £10 so even at £260 it was a very good deal and it arrived in 2 days, now thats service.

Quick question folks, I've been reading about this lens over at Pentax Forums and some people have suggested that it can cause severe purple flare on a Digital Body, is this the case as I've been fairly keen on grabbing one.

The other option I've been offered is a Phoenix 100mm f3.5 from a guy in the States correct me if I'm wrong but I believe this is the same as the Cosina/Vivitar lens?

Did you read the posts before yours?

The 100mm Cosina/Vivitar/Phoenix is supposed to be pretty damn good, especially for the price. By far the least expensive AF macro lens.

Well I've bought Mike's Vivitar 55mm to give that a go for now!

The answer to your question lies in the above comments Chris. I never noticed it but tended to shoot at larger apertures. IQ is outstanding at f2.5. It's better than the Cosina, which I wouldn't pay more than £50-ish for (manual focus version), but the Cosina's still pretty good.

The Vivitar 55mm f2.8 Macro has a formidable reputation.

Using my PKA adaptor on the Tamron 90mm f2.5. It shows a max available aperture on my K-x of f4.0. This happen for anyone else? Never noticed previous as used it as a macro. But wanted to try it wide open for portrait work.

The lens may be misreporting. There's no guarantee that non-Pentax lenses, especially o0ld ones, will show up correctly on newer bodies.

You can shoot wide open by using the aperture ring in AV mode. Would be worth checking the results against what you get shooting at what your camera is telling you is f4.0, i.e. is this a lens communication error, or is it refusing to stop down.

Thanks - did a rough and ready shoot at my laptop screen and do believe there is a difference when I manually move the aperture to f2.5, though the recorded data of the shot still shows f4.0. Will test further, when I'm not supposed to be working

Your PK/A mount may not be working properly - some of them appear to suffer from an issue where threadlock has seeped through from a screw near the electrical contacts on the mount face. This threadlock isn't easily visible but effectively insulates part of the metal mount from one of the contacts on the camera which causes spurious behaviour with the aperture readings.

If you clean the area of the metal Adaptall mount flange with a solvent based cleaner (such as nail varnish remover) about 15mm each side of the electrical contacts, it may help. I have 'fixed' one of my PK/A mounts with a similar problem this way. Some people advocate cleaning the mount face near the electrical contacts with fine emery paper, but I wouldn't recommend this because it damages the surface of the mount and also creates dust that could get into the lens or camera body.