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11-10-2011, 03:39 PM   #31
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I'm actually very close in obtaining Tamron 90mm for reasonable price from another member here.
It beat the Lester dine kit that some members recommended as well due to the weight / no AF for other general usage.

QuoteQuote:
* For farther work and lotsa mag: Any affordable 90-100-105mm A-type or AF macro lens; 4-6 deglassed 2x TCs.
QuoteQuote:
#1: For a non-macro lens, yes. For a macro lens, the MFD doubles. A non-reversed lens cannot focus closer than its focal length.

#2: Light is cut by 2 f-stops. So at 100/2.8 lens with MFD=10cm, with a 2x TC, becomes a 200/5.6mm lens with MFD=200mm.
So Rico, even if I deglass the 2xTC I will cut 2 f-stops ? So the 90mm tammy would become 180mm F4 ? What kind of mag ratio I would obtain on the mfd ? and if the effect is multipled 6 2x TC would = 12:1 mag ?

This deglassed TC option is highly desirable for me since I'll keep farther MFD from the subject

11-10-2011, 04:03 PM   #32
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QuoteOriginally posted by Azzy Quote
It beat the Lester dine kit that some members recommended
It beat the who kit? Um, not sure where you got that info from - care to share?




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11-10-2011, 04:09 PM   #33
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QuoteOriginally posted by RioRico Quote

A Lester Dine dental-macro lens with a built-in ringflash. Can't be beat!
from what a gather its pretty much the vivitar 100m s1 macro lens which has quite a cult status in macro world...
11-10-2011, 04:16 PM   #34
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QuoteOriginally posted by Azzy Quote
from what a gather its pretty much the vivitar 100m s1 macro lens which has quite a cult status in macro world...
The Vivitar S1 2.5 105mm <- Same lens as the 105 2.8 Lester Dine both manufactured by Kiron. The Tammy is a good choice, it is however not as good as the Kiron 105's optically (although you could PP to get better results), it does have the advantage of being AF which may come in handy if shooting other things besides macro.



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11-10-2011, 04:50 PM   #35
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Which Tamron 90 are we talking about? 1:1 or 1:2? Is it an "A" type lens?

Here's the effect of adding a de-glassed TC to a 90mm non-IF lens.
20mm thick TC, 1:1 90mm lens; m = (90+90+20)/90 -1 = 1.2x, effective f-stop multiplier ~ 1.2x
20mm thick TC, 1:2 90mm lens; m = (90+45+20)/90 -1 = 0.72x, effective f-stop multiplier ~ 0.72x

30mm thick TC, 1:1 90mm lens; m = (90+90+30)/90 -1 = 1.33x, effective f-stop multiplier ~ 1.33x
30mm thick TC, 1:2 90mm lens; m = (90+45+30) /90- 1 = 0.83x, effective f-stop multiplier ~ 0.83x

Adding a TC behind a lens does NOT change the working distance, and the factor increasing the magnification is the same as the factor increasing f-stop.

That is, if a 2x TC is added behind a lens, working distance does not change but both magnification and f-stop are increased by 2x.

I just tested to make sure this is the case.

Last edited by newarts; 11-10-2011 at 05:19 PM.
11-10-2011, 05:07 PM   #36
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QuoteOriginally posted by newarts Quote
At 1:1 mag the working distance is 2X focal length - in this case, 200mm.
Correction noted and applied. Thanks!

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Be aware that TC's are often only about 20mm thick so a de-glassed TC won't increase the magnification of a long focal length lens by much.
All four of my PK 2x TCs measure thicker than that. An Albinar M-type and two 2 deglassed A-types (Focal and Promaster) measure 26mm; a Cambron M-type measures 31mm thick.

No, these won't significantly boost magnification of longer glass. They are useful only with a limited subset of lenses. My A-type and AF collection is rather small. One TC on a 28mm lens demands a working distance only about 1in in front of the lens; too close. I can use one or both on the 35-70 and a 50mm. Using both on a 135mm doesn't put me into macro territory; ditto with zooms in the 70-210mm range except at the short end..
11-10-2011, 05:11 PM   #37
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QuoteOriginally posted by newarts Quote
Which Tamron 90 are we talking about? 1:1 or 1:2?
My experience is with the 90mm SP Di 1:1 and guessing that is the one he is referencing...





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11-10-2011, 05:44 PM   #38
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Yeah its the 90mm macro DI 1:1...so If I understood newarts correctly, to get 2:1 mag on the tamron I would need a 90mm thick ext tube / deglassed TC ? (90+90+90)/90-1 ?


Last edited by Azzy; 11-10-2011 at 05:50 PM.
11-10-2011, 06:01 PM   #39
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QuoteOriginally posted by joe.penn Quote
The Tammy is a good choice, it is however not as good as the Kiron 105's optically
In what ways is the Tamron not as good as the Kiron optically? Any examples showing the difference would be much appreciated.
11-10-2011, 06:10 PM   #40
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QuoteOriginally posted by newarts Quote
.

At 1:1 mag the working distance is 2X focal length - in this case, 200mm.



Be aware that TC's are often only about 20mm thick so a de-glassed TC won't increase the magnification of a long focal length lens by much.

A standard 2X TC behind your Tamron zoom should give about 1:1 magnification.

Finally, the working distance for a Raynox 150 on a 300mm lens focused at infinity (1.4x) isn't bad; about 214mm ~ 8.3" a little more than a 100mm macro lens at 1:1
I didn't know how I missed this post....I thought Raynox working distance is pretty close ~4"
The tamron 90mm MFD is 3.9" or 99mm...so with the raynox it pretty much double the MFD for 1:1 mag!!!!

Is there any reason (aside having AF portrait lens) picking the more expensive 90mm tamron over this combo ?
11-10-2011, 06:11 PM   #41
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QuoteOriginally posted by Azzy Quote
Yeah its the 90mm macro DI 1:1...so If I understood newarts correctly, to get 2:1 mag on the tamron I would need a 90mm thick ext tube / deglassed TC ? (90+90+90)/90-1 ?
Yes.

A simpler way (although the image quality might not be as good) is to just use a 2X teleconverter.
11-10-2011, 06:29 PM   #42
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QuoteOriginally posted by Azzy Quote
...
Is there any reason (aside having AF portrait lens) picking the more expensive 90mm tamron over this combo ?
Well, the 90mm Tamron might be a little better IQ up to 1:1, but looking at the results people get with the Raynox on a good zoom, the 90mm Tamron cannot be a whole lot better. If the photos will be displayed electronically then I'll bet that any differences will be hard to see.

One drawback of the Raynox route is the edges of the photo won't be as sharp as the center. This makes no practical difference with natural subjects.

It might help you to spend a few minutes looking at the long Raynox Macro Club thread to see what quality to expect: https://www.pentaxforums.com/forums/lens-clubs/74221-raynox-macro-club.html

If you'd like better quality put an el-nikkor 50:2.8 on a bellows for less than $100. Use a glass-less PK/A TC to trick the camera into thinking the bellows is an A type lens. There are other tricks available to fool the camera so the automatic flash will work with an inexpensive bellows.
11-10-2011, 07:00 PM   #43
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QuoteOriginally posted by Laurentiu Cristofor Quote
In what ways is the Tamron not as good as the Kiron optically? Any examples showing the difference would be much appreciated.
Yup, I am interested too. Please put up some lens resolution test results (no pixie dust or pixie dungs, please!). Meanwhile, I did find this little snippet from this article: Pentax Lens Review by Peter Spiro

Some recent advertisements from Carl Zeiss claim that the Zeiss Planar T 60mm macro lens can resolve 150 lines per mm. Perhaps one should expect no less from a lens that sells at a discount mail order dealer for about US$800. If true, this would give it a higher resolution than any lens ever tested in Modern Photography. The peak I found there was 110 for a 90mm macro by Tamron. Of course, this is the best resolution at the best f/stop for the lens.

Please read the last two sentences from the above paragraph...
11-11-2011, 12:29 AM   #44
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QuoteOriginally posted by excanonfd Quote
The peak I found there was 110 for a 90mm macro by Tamron.
Was that the adaptall version? Someone had posted old reviews (from Modern Photography maybe?) comparing macro lenses and the 52B came out much better than the VS1 and pretty much anything else. Can't find that post now though.
11-11-2011, 01:01 AM   #45
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QuoteOriginally posted by excanonfd Quote
Originally posted by Laurentiu Cristofor Quote
In what ways is the Tamron not as good as the Kiron optically? Any examples showing the difference would be much appreciated.
Yup, I am interested too
I have the Tamron 90/2.5 adaptall2 with belonging TCx2, new Tamron90/2.8 AF, new Sigma105/2.8 AF, fujinon55 w belonging tube, pentax M50/4 + tube + pentax TCx2 + pentax TCx1.4, bellow, multiple sets of tubes, tried reverse ring on many of primes - but no Kiron.

I havent try stacking primes, like 20/28/30/50 on 135/150/200.

I though modern optics with AF on the Tamron90/2.8 and the Sigma 105/2.8 should be at least equal the Kiron if not better due to newer coating and such?
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