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10-15-2010, 12:04 AM   #1
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Vivitar S1 90 PK + 1.4x TC versus Vivitar 90 FD + mount TC adapter

this is an image comparison test between the same type of lens but with different TCs attached on each lens. one lens used a Tamron 1.4X TC while the other one used a generic FD/K mount adapter which acts as a TC with a mag value of 1.43x approx. each of the images are shot at f2.5 and f4 respectively. shot from close range to mid range to test for sharpness, contrast, and signs of IQ degradation. all the jpeg images are converted from RAW. no sharpening and contrast adjustments on all images were made during the conversion. shot under tungsten lighting. no flash was used in this experiment and certainly no animals were harmed as well.

important notes or summary below the images.



*at close range distance

90 + FD/K adapter at f2.5



90 + 1.4x TC at f2.5



90 + FD/K adapter at f4



90 + 1.4x TC at f4





*slightly past midrange distance

90 + FD/K adapter at f2.5



90 + 1.4x TC at f2.5



90 + FD/K adapter at f4



90 + 1.4x TC at f4





*around mid range distance

90 + FD/K adapter at f2.5



90 + 1.4x TC at f2.5



90 + FD/K adapter at f4



90 + 1.4x TC at f4



*note: for anyone interested on looking further at the images, you can see the full resolution of the images at this link >>> Flickr: Pentaxor's Photostream

findings: as you can, the differences between the two lenses don't look that too obvious at small prints or web viewing. although there are noticeable signs, it becomes more apparent as you view the images at full resolution.

what is noticeable using the 1.43x FD/K mount adapter is the loss of contrast and some sharpness on the images as compared to the 1.4x Tamron TC. the differences don't look that obvious at close-up or macro distance, but as you move to closer infinity, the difference becomes much more apparent. the IQ suffers at infinity, although stopping down would seem to easen up the problem a bit but not by much and still find it subpar and unacceptable. I did not include those images shot at infinity here since that particular test was done hastily and may contain testing errors/discrepancies which would void the results, although initial impressions and based from what I saw evidently show obvious IQ weakness and degradation with the FD/K adapter.


but at close distance not more than 5ft, the IQ doesn't seem that worse but quite acceptably good. I also noticed that at close up to mid range, the IQ sharpness difference between the 2 lenses vary from half-stop to a stop difference. although contrast remains weak. I tried post-processing the FD/K results (not the ones posted here) increasing the clarity, sharpness, and contrast. I tweaked it at the same level of that of the Tamron results. the FD/K results can even be way better than the Tamron by tweaking past it in terms of those IQ parameters mentioned.

*problems encountered on the FD/K adapter and Tamron adapter.

as you may know, applying an adapter may and can affect your images. also depends on the type of adapter used. it can degrade the IQ of the photos.

the FD/K adapter shows a hazy and low contrast images. also it shows some halos/glow around images especially under bright conditions, more so at infinity. this maybe due to the inferior glass corrective element on the FD/K adapter. also, it shows traces of CAs, which is magnified or common with the use of a TC optic. the Halo/Glow and CA becomes less relevant or non-existent by stopping down further. it can vary from f4 to f5.6 for the CA, and f8 to f11 for the Halo under bright conditions.

the Tamron on the other has very good contrast and solid images from close up to infinity. sharpness and detail are very much preserved. the Tamron TC also show the same traces of CA. although the level or intensity of the CA is pretty solid or stronger compared to the FD/K CA which has a light glowy CA. this must be due to the better optical elements used on the Tamron TC to retain sharpness and contrast. the lens coating could be a factor as well. CA becomes less relevant or non-existent from 5.6 to f8.

a stand-alone lens and cropped image of the S1 90mm shows that it has the superior or best IQ compared against both lenses with the respective TC on them. also it has a much shallower DOF compared to the two.

my initial conclusion would say that the FD/K adapter is a nice tool for people who wanted to use their old and cheaper FD lenses on any modern day digital camera with a different mount. although not perfect, it can work well with good post-processing skills and with great lenses.

follow-up on the infinity image testing would be done at a later time.


Last edited by Pentaxor; 10-15-2010 at 02:02 AM.
10-15-2010, 05:27 AM   #2
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interesting observations and while much better controled than my informal testing, the results seem to be consistent.

I have only played with the adaptor, and it's nikon AI/PK counterpart with the standard film "kit lens" either the canon or nikon 50mm F1.8 and I too found the blooming seemed to be more noticable when focusing out at bright objects 20-30 feet away but the close focus seemed pretty good, as you have also shown.

The real problem I had, which you seem to have overcome, is a way to compare the lens plus adaptor heads up for fair comparison by using a 1.4x TC and the same lens with PK mount.

I would be interested when you can put some more controlled, longer focusing distance tests up.
10-15-2010, 09:37 PM   #3
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QuoteOriginally posted by Lowell Goudge Quote
interesting observations and while much better controled than my informal testing, the results seem to be consistent.

I have only played with the adaptor, and it's nikon AI/PK counterpart with the standard film "kit lens" either the canon or nikon 50mm F1.8 and I too found the blooming seemed to be more noticable when focusing out at bright objects 20-30 feet away but the close focus seemed pretty good, as you have also shown.

The real problem I had, which you seem to have overcome, is a way to compare the lens plus adaptor heads up for fair comparison by using a 1.4x TC and the same lens with PK mount.

I would be interested when you can put some more controlled, longer focusing distance tests up.
thanks Lowell. I will do that for some time. I can't do some outdoors because of the weather during the past days. today was great but got no time since I was busy doing other stuff.
10-24-2010, 10:24 PM   #4
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here are the infinity focus test shots. as before, the IQ suffers for the 90mm + FD/K combo. the halo/haze effect seems to originate for the lack of further correctional elements that would improve or maintain the sharpness and contrast. sharpness and the halo/haze effect seem to improve a little as you stopped down further into smaller apertures but not as good as that of the 90mm + Tamron TC. also the IQ is worse for the FD/K at these focus range. what is interesting is that the Tamron TC displays higher CA compared to the FD/K adapter. it also displays a bit of a glow or blooming but not as bad, IMO as that of the FD/K adapter. it also shows at f4 apertures although there are times that it looks worse for the Tamron TC but altleast the contrast and sharpness as well-maintained ang gets better by a mile stop after stop.

FD/K at f2.5



Tamron TC at f2.5



crop sizes


FD/K



Tamron TC




as a summary: I dont recommend using the FD/K for shots at infinity focus or anything midrange.

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