SMC Takumar 50/1.4, over hyped or did I get a bad copy?

[mark232]

Hello all,
I finally got around and got myself a takumar 50/1.4, after hearing about a lot everywhere and many of my favorite youtubers putting it in their top 10 lenses.
I mostly use soviet lenses with the pixco speedbooster on an apsc sony sensor, I get edge to edge sharpness wide open with the Jupiter 37a, and the Jupiter 21m, and I need to step down other lenses a little bit to get that sharpness.
but when I tried the takumar, I was very disappointed(sample images below), the edges are very soft until f8 even without the speedbooster, unlike what I read everywhere on the internet about its sharpness wide open.
I was wondering if that's what I should expect from this lens?
I mean, why would you buy an f1.4 lens just to step it down to f8?
the speedbooster is certainly cheap but I don't notice any major softness caused by it on soviet lenses, could it be a compatibility issue? I mean, is it a possibility that certain lens schematics don't work well when combined with that speedbooster? if someone has tried this lens with any speedbooster please tell your experience.

some details about my copy:
fungus-free, looks very clean and lightly used
SN: 4630723
Super-Multi-Coated Takumar 50 1.4 (7 elements)
de-yellowed upon arrival
it didn't fit the speedbooster because of the aperture pin and I had to grind it down.
the most rear glass element was loose and tightened more than it should, it was focusing past infinity because of that and I had to rotate it back a little and adjust infinity focus.


#1 smc takumar 50/1.4 @ f1.4 with m42-nex pixco speedbooster Imgur: https://imgur.com/laltSKi


#2 smc takumar 50/1.4 @ f5.6 with m42-nex pixco speedbooster Imgur: https://imgur.com/imuKCWP


#3 smc takumar 50/1.4 @ f8 with m42-nex pixco speedbooster Imgur: https://imgur.com/aImyKJS

[kiddo]

Hi and welcome to this wonderful forum

[kiddo]

[mark232]

[kiddo]

Regarding "the most rear glass element was loose and tightened more than it should, it was focusing past infinity because of that and I had to rotate it back a little and adjust infinity focus" , I did find that infinity could be adapter issue not to be adjusted 100%(most of the cases , would just pass infinity by very little and that would be considered ok), or it could be the lens issue .
Having has the rear group loosen ,would mean someone else before you had it opened, , so, many things could have happened , not only rear group unproperly tighten, maybe focusing helicoid not fitted right or front group not properly adjusted , probably some othef reasons also .
If you're good on dismantling lenses (like me) and putting 'em back together (here's where I fail lol) you might be able to fix it(some lenses have shims to adjust, I'm not sure this is your case) , otherwise ,if there's any way to return the lens to the seller , might be the best choice.
Could be possible that some element would ve wrongly fit inside it's group? Not sure about this, as in this case far edge corners wouldn't focus at all I suppose.
Try no to tighten the lens all the way inside the adapter , to check infinity focus (many m42 would have this issue).

[D1N0]

The takumar isn't popular for shooting charts so well. It is soft wide open, especially the older ones without SMC coating. Makes it a great portraiture lens. If you rear element has problems that will affect lens performance in big way. A speed booster in the equation makes it hard to tell what is causing what. I bet that at longer focussing distances the corners will be better though.

[caspert79]

Curious how this lens does in real life. Do you have examples?

[visualopsins]

Welcome mark232!

First example image so bad definitely indicates something wrong with lens -- probably not a "bad copy" (are there ANY "bad copy" Takumars?), probably reassembled incorrectly perhaps with a reversed element -- front and rear groups remove as units very easy; compare element orientations with diagram.

[RokkorDoctor]

The lens diagrams I could find on-line suggest the rear element looks near symmetrical to the eye, but measurement will almost certainly show that it isn't.

My best guess would be that the rear element was remounted back-to-front, or that an internal spacer (if there are any) was mounted back-to-front.

[Dejan]

Maybe it doesn't like that speedbooster (though I've no experience with those, but they are known to increase some aberrations and distortion, especially around the edges). I'd test it without it just in case. Anyhow, the lens shouldn't perform this way for sure. It's not that great wide open, but there isn't such smearing, just low resolution and contrast (plus chromatic and spherical aberrations).

[Rolf]

I agree with Dejan.

Forget the speedbooster and replace it with a normal adapter m42 to Sony Nex without any additional glass.

[D1N0]

I shot this with my super-takumar 50/1.4 (7 element). Poster is A2. Not nearly as much distortion as your copy, despite being soft especially towards the edges.

[titrisol70]

Agreed, while the ST 50/1.4 tends to be soft in the edges, yours is way too much.
If you had to adjust any of the elements of the lens, there is a problem. I have never had to touch the glass on any of the examples I got.
So m guess is that someone tried to open it and assembled it incorrectly, thus either of the inside elements is nos properly spaced or backwards.

Also by the S/N your is a late 7 element, and most probably is coated with several layers
See behind the A/M switch and check if the number is 37802 or 37801

[titrisol70]

Takumarology pages:
37802 (late) 8 blades iris
https://takumarguide.weebly.com/1--14--50-37802.html

37801 Most abundant 6 blade iris
https://takumarguide.weebly.com/1--14--50-37801.html

[mark232]

UPDATE:

Thanks a lot for all of your suggestions, I took the glass elements apart and found that the retainer between the second and third glass elements in the front group was not tightened at all by someone who tried to tinker with it in the past, I've put it back correctly and also tightened the rear element back to its original position and it's working fine now.
it is truly superb, it's still a little soft on the edges but nothing like how it used to be and way better than all of my fast lenses.

#1 here's the chart after fixing the lens, shot handheld wide open (focus might be a bit off)

[mark232]

[mark232]

[mark232]

[mark232]

[mark232]

[mark232]

[Rolf]

Ok, my experiences with adapters with add. glass were very bad. So for me no more any option, but if it will work for you why not.

[D1N0]

A speed booster is the opposite of a tele-converter. Usually that will give better results since aberrations are shrunk instead of enlarged. But OP made it clear the fault was with the rear element not being installed correctly, which explains a lot.

[visualopsins]

[titrisol70]

You didi great for less than $10!
Asahi (Pentax) gave their lenses part numbers, that were stamped in the back of the A/M button
Depeding on the characteristics.
37800 first model of 7 elements - Thorium element included
37801 second model (white dot on f/2) - Mechanical differences
37802 8 blade iris and coated - Late model, mostly super-multi coated, f/2 has number

By your S/N yours should be 37802 or 37801