[Diffusion]

Thanks to a post in the dpr forum, I have recently acquired a 70-210/3.5, and I am very happy with it so far.

I was thinking of adding a TC to it, ideally the TC would complement maybe a future 90mm Macro Adaptall.

So, I have two questions. There are quite a number of different Adaptall-2 TCs. Is there one that is better than others?

Regarding the 90mm macro, is the 2.8 1:1 better than the 2.5 1:2? Or vice versa? I realize without a TC or extension tube, the 2.5 is not life sized. I think the 2.8 is rarer, harder to find, and more expensive.

Thanks for the advice.

D.

[Nesster]

The BBAR Flat Field 2x 01F goes between lens and adaptall-2 mount, as does the dedicated extension tube. I wasn't aware that there are many adaptal-2 tc's... except the special purpose 200F.

The TC is pretty good, works with any of the adaptall-2 lenses, though I find I want to stop down a bit using it. The extension tube really works only with the 2.5, but I have managed to use it with other lenses... and the tube retains better optical performance

[Stringmike]

I use the same lens mostly without a TC, but have tested it with the Adaptall 1.4 TC. This provides a very nice 100mm to 300mm combination. I've also used it with the Pentax 1.7AF TC and find it does autofocus very well, but the combination is a tad soft at the long end. I would venture that the 2x TC might push the lens a bit far.

Mike

[monochrome]

I was only aware of three Adaptall-2 TC's. These two SP TC's fit the 90/2.5 (both cosmetic versions) and literature states they can be used with other lenses, including certain zooms:

Tamron SP 1.4X Tele-Converter Model 140F
Tamron's literature states that this converter is designed for lenses with a focal length of 90mm and longer. Nevertheless this converter performs well with all Tamron zoom lenses which have a stationary master group (the rearmost group of lens elements). This converter can also be used with many Tamron wide to tele zoom lenses for doubling macro magnification, and usually results in better off-axis macro performance.

Tamron SP 2X Tele-Converter Model 01F
Tamron's literature states that this converter is compatible with all Tamron fixed focal length lenses of 90mm and longer. This converter also performs well with all Tamron zoom lenses which have a stationary master group (the rearmost group of lens elements), and can also be used with many Tamron wide to tele zoom lenses for increasing maximum macro magnification by 1.4X.

Tamron SP 2X Tele-Converter Model 200F
Tamron also produced the very rare SP 2X Tele-Converter Model 200F. The 200F converter can be used with Tamron's 135mm F/2.5 model 03B, all manual focus SP 300mm F/2.8 lenses, SP 300mm F/5.6, SP 400mm F/4, Adaptall and Adaptall-2 70-350mm lenses, SP 200-500mm F/5.6, Adaptall 200-500 F/6.9, plus the SP 350mm F/5.6 and SP 500mm F/8 mirror lenses.

Tamron Adaptall-2 Information Website

[Diffusion]

Thanks for the comments so far.
I think the varifying notations (BBAR, 01F, etc..) for same TC's confused me.

Any thoughts on the 90mm 2.8 vs 2.5?

I use the same lens mostly without a TC, but have tested it with the Adaptall 1.4 TC. This provides a very nice 100mm to 300mm combination. I've also used it with the Pentax 1.7AF TC and find it does autofocus very well, but the combination is a tad soft at the long end. I would venture that the 2x TC might push the lens a bit far.

Mike

I think you are right. I did notice that 4.0 is a lot sharper than 3.5 on the lens. Also, it PF/CAs with the best of them wide open.
I guess I should look for a 1.4TC, a 100 to 300mm lens would be nice. Or cropping would work, too.

Thanks again for all opinions.

[stevebrot]

Thanks for the comments so far.
I think the varifying notations (BBAR, 01F, etc..) for same TC's confused me.

Any thoughts on the 90mm 2.8 vs 2.5?

BBAR is the proprietary Tamron coating technology. Most Adaptall-2 lenses have it.

01F is the model number. It is common in Tamron circles to refer to a lens or TC by its model number since several different designs were made to similar specs over the years.

The SP 90/2.5 52B/52BB are both 1:2 lenses and require a 2X TC for 1:1.

The SP 90/2.8 B57-100 delivers 1:1 without a TC

All Tamron 90mm Macro lenses have excellent reputations.

Steve