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11-16-2009, 07:00 AM   #1
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Lens value question/inquiry: Tamron 90mm F2.5

Just a quick question... Have an opportunity to purchase a Tamron Adaptall 90mm F2.5 (not sure which one) with PKA adaptall mount. I wasn't really looking for one, but a local Pentax user mentioned he had one. I know this is a sharp 1:2 macro and realize the PKA adapter is hard to come by. Assuming good optical condition, what's a fair value for this combo? Thanks!

11-16-2009, 10:13 AM   #2
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The lens itself (if in good shape) should go for anywhere from $75-125...the one with the 55mm filter thread is worth a bit more than the 49mm version.

The Adaptall mount's "market value" is $60-100.

I guess it depends on if they know what the lens is worth or not
11-16-2009, 02:41 PM   #3
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Thanks, I appreciate the information. I'm going to check everything out tomorrow.
11-16-2009, 03:13 PM   #4
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See Tamron SP Adaptall-2 90mm F/2.5 Model 52B for info.

No optical advantage for the later model #52BB, just cosmetic differences. They work well with the dedicated Adaptal 1.4x and 2x TCs and with extension rings. I like a Tokina/Katana auto 2x TC with the optical element unscrewed to get to ~1:1 when necessary.

Anything under $150 for both would be a real bargain. $180 would be fair.

If you happen to notice that the f-stop doesn't always appear in the DSLR viewfinder, don't be too alarmed. Shoot a few shotsat different aperture settings to verify (using the review data) that the lens actually stops down. You can fix or work around the display issue.

H2

11-17-2009, 05:21 PM   #5
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Well, I just picked it up! Don't feel too guilty as I just got a refund from my mortgage company. It is the 55mm filter version (whichever that equates to) and it appears to be overall good shape. The body has some wear, but the optics looks great. Looking forward to spending some time with it. There appears to be an optional lens hood available for this... is it worth finding one?
11-17-2009, 05:27 PM   #6
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QuoteOriginally posted by joeyc Quote
Well, I just picked it up! Don't feel too guilty as I just got a refund from my mortgage company. It is the 55mm filter version (whichever that equates to) and it appears to be overall good shape. The body has some wear, but the optics looks great. Looking forward to spending some time with it. There appears to be an optional lens hood available for this... is it worth finding one?
With both the #52B and the #52BB the lens hood will significantly increase contrast and reduce flare, since the front element is very close to the edge of the body. I believe there are hoods for this available on ebay right now.

Last edited by monochrome; 11-17-2009 at 08:28 PM.
11-17-2009, 05:32 PM   #7
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QuoteOriginally posted by joeyc Quote
There appears to be an optional lens hood available for this... is it worth finding one?
While you're looking for the "proper" lens hood, try this idea:



You may like it so much you forget about the lens hood.

I myself don't use the original Tamron lens hood anymore.
11-17-2009, 06:12 PM   #8
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QuoteOriginally posted by monochrome Quote
With both the #52B and the #52BB the lens hood will significantly increase contract and reduce flare, since the front element is very close to the edge of the body. I believe there are hoods for this available on ebay right now.
Thanks for the heads up. What you're saying about contrast and flare is right along with lines of what I was thinking.

11-17-2009, 06:12 PM   #9
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Thanks for the reminder - I recall you shared this before with some of your other lenses. I may do something along these lines.

QuoteOriginally posted by SOldBear Quote
While you're looking for the "proper" lens hood, try this idea:



You may like it so much you forget about the lens hood.

I myself don't use the original Tamron lens hood anymore.
11-17-2009, 08:30 PM   #10
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QuoteOriginally posted by SOldBear Quote
While you're looking for the "proper" lens hood, try this idea:



You may like it so much you forget about the lens hood.

I myself don't use the original Tamron lens hood anymore.
I like this! Do you have some sort of "formula" to determine what kind of step-down rings to use depending on the lens? Or is it more of a trial-and-error process?
11-18-2009, 12:09 PM   #11
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QuoteOriginally posted by photogerald Quote
Do you have some sort of "formula" to determine what kind of step-down rings to use depending on the lens? Or is it more of a trial-and-error process?
Yeah, it's mainly trial and error. I just stack a bunch of step-down ring adapters to the lens and try to meter and/or focus. If the metering changes or focusing becomes more difficult, I go back one step of step-down ring. 50mm lenses in particular work very well, even on a film camera.





So far, all the lenses I try from 24mm to 90mm focal length can go down to 30.5mm opening. The longest is Tamron 90mm macro F/2.8, the shortest is Pentax-M 24mm F/2.8. The DA 21mm Ltd. can go down to 30.5mm too but it needs a thin 49-37mm ring (Sonia). The B&W ring, only 1mm thicker, results in vignetting. In the photo, the DA 70mm is on the camera, the other two lenses are DA 21mm and DA 40mm (with its original lens hood).





The Vivitar 135mm Close-Focusing F/2.8 can go down to 49mm from 62mm. I then add a Pentax 49mm hood:





This kind of lens hood doesn't work well with zoom lenses. They should use their dedicated hoods.

Last edited by SOldBear; 11-18-2009 at 02:26 PM.
11-18-2009, 12:57 PM   #12
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I do have a fully tricked-out 52BB model. I got the lens itself cheap, with a Nikon Ai adaptall. Over time I found the hood - it's pretty deep, bayonets into place, made of thinnish plastic - and the extension tube, and I have a 2x flat field converter. With either ext or 2x in place, and the hood, the lens gets to look pretty long. The tube is better optically (natch) than the 2x, but the tube is 'dedicated' in that the adaptall has two tabs for the aperture feelers, and on the tube one is fixed at f/2.5. So it really works only if you have another f/2.5 adaptall... I've used in anyway with other tamrons.



On a K100d, 2x converter, focus around 2 ft, and the shade.
11-19-2009, 01:45 AM   #13
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QuoteOriginally posted by SOldBear Quote
Yeah, it's mainly trial and error. I just stack a bunch of step-down ring adapters to the lens and try to meter and/or focus. If the metering changes or focusing becomes more difficult, I go back one step of step-down ring. 50mm lenses in particular work very well, even on a film camera.

This is very cool! I'm surprised to hear that this works even on film cameras - I would've expected there to be vignetting.

QuoteOriginally posted by SOldBear Quote
So far, all the lenses I try from 24mm to 90mm focal length can go down to 30.5mm opening. The longest is Tamron 90mm macro F/2.8, the shortest is Pentax-M 24mm F/2.8. The DA 21mm Ltd. can go down to 30.5mm too but it needs a thin 49-37mm ring (Sonia). The B&W ring, only 1mm thicker, results in vignetting. In the photo, the DA 70mm is on the camera, the other two lenses are DA 21mm and DA 40mm (with its original lens hood).

This concept of an "inverted hood" is really neat, but I find it counter-intuitive. How come it works? It sort of makes you wonder if they could've made the front elements smaller? But I'm no optician so maybe there's something that I'm missing. Anyways, I really like this idea as it looks good, saves space, and affords more protection to the front element.

Actually, I just thought of something - would this setup be more likely to cause vignetting when focusing on closer subjects?

QuoteOriginally posted by SOldBear Quote
The Vivitar 135mm Close-Focusing F/2.8 can go down to 49mm from 62mm. I then add a Pentax 49mm hood:





This kind of lens hood doesn't work well with zoom lenses. They should use their dedicated hoods.
Yes, I like this a lot! I hate carrying bulky hoods for my telephoto lenses. Time to go hunting for some cheap step-down rings!

Thanks again, and by the way, apologies to joelc for this thread hijack...
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