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Playing around with a stock 18-55 and a Sigma 70-300 ...
Now, with an SMC Takumar 105 and a CZJ Flektogon 35 too ...

Sunday, April 24, 2011

Cleaning haze: Tamron SP90 f/2.5 (52B) ...

Being a rainy day, i decided to spend some time cleaning a lens of my preferred seller, a Tamron SP90/2.5 Macro (the 52B model, with a 49mm filters thread) ... The lens was affected by some kind of internal haze and some strange internal reflections, which made me almost skeptical about the success of the operation (read why at the end of this post)...

01 - Tamron SP90 Fix - _IGP5301

Do you want to know more ? If no, then you can fly away from this page. If yes, then continue reading, but before:


So, after the legalese, let's start the game ...

Since the haze seems to be between the first two front elements, start by unscrewing the front ring using a sink cap:

02 - Tamron SP90 Fix - _IGP5302

Once the front ring removed, you will notice two concentric rings with notches for a spanner wrench. The ring to remove now is the inner one (if in doubt, check the picture on the Flickr photostream, it has notes on it):

03 - Tamron SP90 Fix - _IGP5304

After removing the retaining ring, CAREFULLY turn the lens upside down: the front element, a spacer ring and a cemented element will slip away from the barrel:

04 - Tamron SP90 Fix - _IGP5305

Here an almost missed shot. I should have switched to a macro lens, to show the haze and a nice fingerprint, probably left by the previous repairman who serviced this lens. Instead, i just took a picture of the elements to clean (grin!) ...

05 - Tamron SP90 Fix - _IGP5306

Being my first cleaning from haze, i didn't know how to attack it, so i started with the usual fungus removal tool, some Cold Cream:

06 - Tamron SP90 Fix - _IGP5309

Since i had to wait some time, i decided to clean the front element too:

07 - Tamron SP90 Fix - _IGP5312

After about half an hour, time to check if the cold cream worked for the haze ... Thus, i removed the dried cream with some Zippo fluid and a q-tip:

08 - Tamron SP90 Fix - _IGP5313

Great surprise, the cell was clear, no more haze or fingerprint :-) ... And yes, i know that i should have taken a macro shot here ...

09 - Tamron SP90 Fix - _IGP5314

After cleaning the front element, CAREFULLY slip in the cemented cell first and the spacer ring after, using some tweezers for the spacer ring (damn framing):

10 - Tamron SP90 Fix - _IGP5315

Finally, after about an hour, the lens is ready for some action:

11 - Tamron SP90 Fix - _IGP5319

The lens was entrusted to me with a Canon EOS third-party adapter mount. Since i didn't have a spare  Pentax-K Adaptall mount for testing, i decided to test the lens on my 5D Mark II ...
A first shot with the lens wide open, at f/2.5:

12 - Tamron SP90 Fix - _MG_9579

Then, another one at f/4:

13 - Tamron SP90 Fix - _MG_9580

I didn't rely too much about the success of the cleaning, but the results are worth the effort ...

Footnote for the curious readers: some haze on inner cells of a lens, typically on cemented cells, denotes a beginning of flaws in the cementing glue. Usually, this kind of damage may be easily fixed by a professional repairman, who has to separate the elements, remove the glue, clean the elements, then realign and glue them again. When i first saw the haze, i was thinking about this kind of flaws, which i'm not able to fix for different reasons (notably, lack of specialized hardware). Nevertheless, i warned the owner of the lens about the possible failure of the cleaning ...
Luckily, the haze has revealed to be a kind of surface moisture (because of a previous bad cleaning ?), which has been easily removed by the cold cream. In the case of a cement flaw, all this would have been useless ...

Again, do not hesitate to ask the services of a professional repairman for servicing this kind of valuable lenses, they are really worth the money ...

Last minute editing: another sample shot at f/4, during a "field test" at the Jardin des Plantes in Toulouse.

Tamron SP90 f2.5 Macro 52B - _MG_9917

If you want to check the full resolution sample pictures, taken with my 5D MarkII, feel free to browse this set from my Flickr photostream.

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Sunday, April 17, 2011

MF Lenses Mania: Voigtländer Color-Ultron 50/1.8

A few months ago, an sudden LBA crisis leaded to the buy of a nice Voigtländer Color-Ultron 50 f/1.8, with an M42 mount.

Voigtlander Color-Ultron 50 f1.8 - _IGP4859

Despite its name, this sample comes from Singapore, according to the copyright on the mount.

Up to now, i haven't been unable to get some spare time for taking sample pictures but, yesterday i decided it was time to go ...

Taking advantage of the sunny day, i brought this lens (and others, too, but this will be the subject of later posts) to one of my preferred shooting locations, the Jardin des Plantes in Toulouse.

Here a sample picture at f/4:

Voigtlander Color-Ultron 50 1.8 - _IGP5003

Here another one at f/2.8:

Voigtlander Color-Ultron 50 1.8 - _IGP4941

For the aficionados, these pictures are straight from the raw files, processed by Silkypix only to adjust the exposure and lowering the contrast, read below why. As usual no Photoshopping (or the like) here ...

My impressions:
  • This lens is really compact (as all the 50/1.8 around) and easy to handle. Nevertheless, it focuses and stops down in the opposite way wrt the classic Pentax lenses (i.e., you turn left to both reach the infinity and stop down the diaphragm).
  • The excellent contrast (a bit excessive, sometimes) makes focusing really easy.
  • The lens is a bit soft when used wide open (samples on my Flickr photostream), but it becomes razor sharp starting at f/2.
  • Only issue found up to now: the lens being an auto-only one, an adapter with an inner flange is required (i don't like too much stop-down pin surgeries). I don't know if this is an issue of my sample, but i found that the pin shall be fully pressed to reach f/16. This doesn't happen with the adapter ring of my Pentax K10D, thus i have been able to stop down only up to f/5.6 (but i'm planning more tests with my 5D Mark II).
If you want to see more sample pictures at full resolution, the (growing) set is available on my Flickr photostream clicking here ...

Coming back soon with new samples with other lenses ...

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