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12-02-2018, 11:14 PM   #136
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QuoteOriginally posted by jddwoods Quote
I have two iterations of this lens: The FA 50 f1.7 (autofocus version) and the M 50 f1.7 which is the manual focus version and for the purposes of this thread, my favorite vintage manual focus lens. Both are nice compact and very sharp lenses. You should enjoy using yours.
I should enjoy my M 50 f1.7, but everything I shoot is tinged yellow. Dad's lens looks so clean and well cared for, not a scratch. It does not see the light of day, and somehow it has this yellow tinge thing going on. I came across this thread, tonight: Removing yellow tint from pentax lenses - PentaxForums.com The discussion concerns exposing lenses giving yellow tinge to UV light and they will clear up. I will give that a try.

12-03-2018, 12:20 AM   #137
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QuoteOriginally posted by mroeder75 Quote
I should enjoy my M 50 f1.7, but everything I shoot is tinged yellow. Dad's lens looks so clean and well cared for, not a scratch. It does not see the light of day, and somehow it has this yellow tinge thing going on. I came across this thread, tonight: Removing yellow tint from pentax lenses - PentaxForums.com The discussion concerns exposing lenses giving yellow tinge to UV light and they will clear up. I will give that a try.
Spent the past hour and a half researching this problem. My camera was set on White Balance CTE which can give a "warm glow." In my case warm was dark yellow antique ugly tinges. It seems to have only affected photos taken with the F/1.7 50mm manual lens, and not any of my automatic lenses, or my old f/2.8 28mm Focal manual lens. Now my lens is clear.
12-03-2018, 06:34 AM - 1 Like   #138
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QuoteOriginally posted by mroeder75 Quote
Spent the past hour and a half researching this problem. My camera was set on White Balance CTE which can give a "warm glow." In my case warm was dark yellow antique ugly tinges. It seems to have only affected photos taken with the F/1.7 50mm manual lens, and not any of my automatic lenses, or my old f/2.8 28mm Focal manual lens. Now my lens is clear.
White Balance CTE stands for Color Temperature Enhancement.

Instead of correcting for a color shift, CTE will exaggerate the color shift in the picture. Sunsets become redder, blue hour photos will be bluer, fluorescent lighting becomes greener, and yellow-tinted lenses become yellower.
12-03-2018, 06:41 PM   #139
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QuoteOriginally posted by mroeder75 Quote
I came across this thread, tonight: Removing yellow tint from pentax lenses - PentaxForums.com The discussion concerns exposing lenses giving yellow tinge to UV light and they will clear up. I will give that a try.
I believe that the yellow tinge that can affect some of the old takumar M42 lenses is due to the radioactive substance in some of the glass. I do not believe these were carried over to the later K-mount lenses.

Glad you found the WB as the problem area.

12-05-2018, 12:13 AM   #140
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QuoteOriginally posted by pschlute Quote
I believe that the yellow tinge that can affect some of the old takumar M42 lenses is due to the radioactive substance in some of the glass. I do not believe these were carried over to the later K-mount lenses.

Glad you found the WB as the problem area.
I think the White Balance is the problem. I will work more on it later. I downloaded an app to my cell phone that measures gamma ray radiation through the cell phone camera lens. My landline is a source of higher radiation than any cell phone. My Pentax camera exudes gamma ray radiation. My manual f/1.7 lens emits none. So, I hope it was the CTE white balance setting, even though my Focal f/2.8 lens seemed to be unaffected by the yellow tinge. I did a few photos in the office and shutting down CTE seemed to do the trick for the f/1.7 lens so far.


I have a family trip scheduled next week to Tucson, and will take the lens with me and experiment with it. It is pretty cool taking photos with 35-year old lenses.
12-06-2018, 10:37 AM   #141
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QuoteOriginally posted by pschlute Quote
I believe that the yellow tinge that can affect some of the old takumar M42 lenses is due to the radioactive substance in some of the glass. I do not believe these were carried over to the later K-mount lenses.
Not so simple. For example, if I remember correctly some SMC Pentax 1.8/55mm are affected.
The use of lanthanum glass continued for at least all the seventies.
Pure lanthanum does not cause yellowing. Unfortunately some batches of optical glass were made with a raw material that contained thorium impurities.
There is a great study available as pdf. I guess it can be downloaded from Marco Cavina web site.
I don't know if there is an html version in english. If not, Google Translate is your best friend.
The article is titled: "HOT LENSES Gli obiettivi radioattivi fra mito e realtà".
It provides plenty of readings of the level of radioactivity of vintage lenses.
The issue of yellowing is also discussed in depth.
12-08-2018, 06:13 AM - 1 Like   #142
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I have quite a few manual focus, film era lenses - certainly 40+ anyway. There are a few that still get a bit of use (and I'm expecting a few more to get used now I have a K1) but one that stands out for me is the Vivitar 28mm F2:

12-09-2018, 01:29 AM - 2 Likes   #143
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QuoteOriginally posted by niblue Quote
There are a few that still get a bit of use (and I'm expecting a few more to get used now I have a K1) but one that stands out for me is the Vivitar 28mm F2:
Buying the K-1 opened a whole new phase for me.
I got interested in vintage lenses, and in photography at large, much more than before.
I could finally use the old K, M and A lenses (plus my three beloved A Star's) on the format they were originally designed for.
A good number of them made little sense on APS-C, but I always refused to part with them, hoping for an FF camera that could never come
Fortunately it did.
When I use fast MF lenses, I found that the larger ground glass, together with a newly acquired O-ME53 focusing aid, allows for much better focusing.
When it's not enough I go for LiveView.
I gave up the hope to see a camera with uncrippled PKAF mount. Though there still is a problems that bugs me.
M42 lenses with tapered back don't cover the original Pentax adapter. Light gets in through the slot of the locking spring, and fogs the picture.
To prevent that, I'm using one of those black elastic bands that are commonly used to tie hair.
I'm wondering if in theory it could be possible to design another locking system that works flawlessly on modern Pentax digital cameras.

Regarding the Vivitar 2/28mm, if you refer to the Kino-made one, also sold as Kinon, I fully agree on your positive judgement.
Both the 2/28mm and 2/24mm were at the same level (or better) as the best OEM optics of the time.
You can't ask for great sharpness wide open, but at least you have the chance to shoot with a lens that fast!
Stopped down it is at least as sharp as a modern, highly expensive prosumer zoom.
The only shortcoming is the diaphragm lever guard that protrudes inside the mount and fouls the two "power contacts".
It is a common trait of Kino lenses in PK mount.
The first time I had it fixed with a lathe.
After that, I decided to use a file, protect with tape the innards of the lens, and shorten the guard a couple of mm the rough way, with a little watchmaker file.
If you find a marker close enough to the original black enamel, the work is almost invisible.
My only gripe is the lack of electric contacts. I would prefer the PKA version, which is as good mechanically and allows for PTTL flash and any possible camera mode.
I know most people complain about oily, unresponsive diaphragm blades. I have been lucky, out of two 28mm examples and one 24mm, none of them had that problem. Maybe they will develop it in the future, who knows...


Last edited by cyberjunkie; 12-09-2018 at 01:39 AM.
01-17-2019, 04:32 PM   #144
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QuoteOriginally posted by cyberjunkie Quote
Buying the K-1 opened a whole new phase for me.
I got interested in vintage lenses, and in photography at large, much more than before.
I could finally use the old K, M and A lenses (plus my three beloved A Star's) on the format they were originally designed for.
A good number of them made little sense on APS-C, but I always refused to part with them, hoping for an FF camera that could never come
Fortunately it did.
When I use fast MF lenses, I found that the larger ground glass, together with a newly acquired O-ME53 focusing aid, allows for much better focusing.
When it's not enough I go for LiveView.
I gave up the hope to see a camera with uncrippled PKAF mount. Though there still is a problems that bugs me.
M42 lenses with tapered back don't cover the original Pentax adapter. Light gets in through the slot of the locking spring, and fogs the picture.
To prevent that, I'm using one of those black elastic bands that are commonly used to tie hair.
I'm wondering if in theory it could be possible to design another locking system that works flawlessly on modern Pentax digital cameras.

Regarding the Vivitar 2/28mm, if you refer to the Kino-made one, also sold as Kinon, I fully agree on your positive judgement.
Both the 2/28mm and 2/24mm were at the same level (or better) as the best OEM optics of the time.
You can't ask for great sharpness wide open, but at least you have the chance to shoot with a lens that fast!
Stopped down it is at least as sharp as a modern, highly expensive prosumer zoom.
The only shortcoming is the diaphragm lever guard that protrudes inside the mount and fouls the two "power contacts".
It is a common trait of Kino lenses in PK mount.
The first time I had it fixed with a lathe.
After that, I decided to use a file, protect with tape the innards of the lens, and shorten the guard a couple of mm the rough way, with a little watchmaker file.
If you find a marker close enough to the original black enamel, the work is almost invisible.
My only gripe is the lack of electric contacts. I would prefer the PKA version, which is as good mechanically and allows for PTTL flash and any possible camera mode.
I know most people complain about oily, unresponsive diaphragm blades. I have been lucky, out of two 28mm examples and one 24mm, none of them had that problem. Maybe they will develop it in the future, who knows...
About the M42 lenses i use a plumbing gasket designed for a sink waste pipe which helps as a light seal, alternatively there are lipped m42 adapters now you don't get infinity focus with these but for portrait work where you want the background blurred this isn't a problem. It's also far easier to change lenses.

I've found an old cobra650 dedicated flash works well it has its own light sensor and is pretty close on getting the exposure right.
01-18-2019, 03:12 AM   #145
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QuoteOriginally posted by niblue Quote
I have quite a few manual focus, film era lenses - certainly 40+ anyway. There are a few that still get a bit of use (and I'm expecting a few more to get used now I have a K1) but one that stands out for me is the Vivitar 28mm F2:
The Vivitar 28mm f/2 lenses are very nice indeed. Which version do you have - Kiron or Komine?
01-18-2019, 03:58 AM - 2 Likes   #146
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current favorite: Mamiya Macro Sekor 60mm f2.8

interesting and not-so-common M42/preset lens....





01-18-2019, 08:18 AM - 3 Likes   #147
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K 28mm f/3.5 because of the wider angle of view. But lately have been shooting all auto focus lenses. I really should slap that 28mm back on again.

01-19-2019, 03:56 AM   #148
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QuoteOriginally posted by Jonathan Mac Quote
The Vivitar 28mm f/2 lenses are very nice indeed. Which version do you have - Kiron or Komine?
I'm pretty sure mine is the Komine one but have heard that both are good.
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