If anyone is thinking about a macro lens the Tamron f/2.5 Adaptall lens is a way better performer than the later f/2.8 version.
Tamron origianally developed an Adaptall 2 mount in the canon EF mount type to fit all eos cameras. However, the true Tamron original items are seriuosly rare items to come by....they were only stocked by Tamron to cater for their 350mm and 500mm mirror lenses.
Hwoever, there now appaers to be loads of after market pattern made mounts on ebay coming from overseas. Great items, and for only about £20 a bargain to boot.
Two minor critisisms people should be aware of tho...I bought one of the after market items not so long ago and it was a little 'sloppy' on the lenses and camera body...not a major worry, just a little off putting if you're use to quality.....particularly where you might be fitting a heavy lens to a larger SLR.
Second critisism...which also applies to Tamron's own mount when it was available.....your chosen Tamron lens will only have a completely manual aperture/iris operation. Takes a bit of getting use to focusing at open aperture f/2.5 then stopping down as desired.....could be a pain if you're doing shots requiring quick operation?!

Aside from using Tamron adaptall2 lenses....why not try Contax mount lenses...if you've got the cash a good carl zeiss lens will deliver some nice results....and contax lens to canon eos /EF body mount adapters are available for a few pounds....for a few extra pounds (about £40) you can even buy them with a facility to provide focus confirmation in your canon camera viewfinder!

The original Tamron lens had no ability to stop down the lens so lenses with a stop down metering switch can't be used as neatly for stop down metering/focussing. This was due to its design for use with mirror lenses with no aperture adjustment. A better method is to use anothe Tamron mount and an adapter from that mount to Canon EF e.g. Nikon or Olympus which are widely available for not much cash. The bonus of an Olympus Tamron mount is the stop down lever on the rim of the mount as in Oly lenses.

Other Tamron lenses e.f. 105/2.5, 135/2.5 have a an on lens switch for stop down metering and open up for focussing.

don't limit yourself to the older adaptall lenses with the M-A aperture manual/auto iris switch....it's all hyperthetical once you put the EF/eos mount or adapter on anyway....the EF mount requires an electronic pulse to stop the iris down at photo taking time.

....tho I can see your point....quicker to move a lever than moving the aperture ring back to the desired aperture .....particularly at speed...

remember too that Pentax DSLR and Nikon DSLR still use the mechanical methods to operate the lenses apertures, so the same sort of problem wouldn't happen with Tamron's fitted with the correct mounts on their DSLR's, as we see on Canon's.......ah blast if only Canon had kept the old FD mount ba humbug...don't take me down that path! Have you seen how cheaply some quality FD fit optics go for....once saw a 300mm f2.8 go for less than £200.....imagine what it would've gone for had it been compatible with current canon kit!?

Hello again.

Can someone please explain, in what circumstances loss of infinity focus arises?

thanks

This is normally due to the fact that the adaptor does not place the lens exactly at the same distance from the sensor as it would be on the native fit camera.

I was also told by a camera repair technician that Macro lens tend to be tuned to close up than for moon shots.

hi there, i have another query...

I have been using the said lens via a contax/yashica adaptall mount on my yashica FRII. however i have noticed that it does not focus at infinity!

Why can this be? is it a fault in the lens or the mount? how can i fix the problem?

I thought such problems only occured when the "distances" were out of calibration, which i read, only normally occurs when trying to adapt lenses to digital.

all help appreciated

Thanks

--------nm.

H4RDY,
Are you using the 90mmf/2.5 version or the later f/2.8 version on your FR11?

I'm a big user of Tamron lenses on the Contax/Yashica mount, but the 90mm I have is the earlier 'metal' f/2.5 (came in later platic shrouded f/2.5 and later stillf/2.8 version...bonus of the later 2.8 was it could go down to 1:1 macro ratio without tamron extention ring)

just some thoughts/ideas....
You're using a mount that these lense were designed to be used with, so there's no arfermarket issues you should have here....assuming everyhting works as it should...
I would take an educated guess that either the C/Y adaptall mount is defective, something come amiss with the FR11 focus screen, or the lenses focus mechanism is out of alignment...the later f/2.8 versions where known to have a weak mechanism there....we've had one in the shop like it.....also the earlier versions are getting to be vintage now, so could the lenses be in need or TLC or has been taken apart sometime in it's long life?

Just to clear up abit of confusion when americans talk about mm I think you will find they are referring to 0.001 of an inch imperial and not a metric mm.

Thanks everyone.

Joe my version is infact the latest f/2.8 version and i have an inkling that it may indeed have been taken apart.

Presumably if i go to an independant camera shop they will know what the fault is and what is to be done to fix it, correct?