135mm seems to have been a very common focal length of lenses. There are many to choose from. Because there was fierce competition, many of them are of good quality. Let see if this lens is one of the good ones…

Pentacon Electric 135mm/2.8
My purchase
I bought the lens on Tradera (swedish ebay) for SEK 57 (about £5) + shipping, without seeing much of it in the images of the ad. I was lucky, it is in good optical condition and only fault is that it is sometimes a little stuck at the aperture. Good ones is seen on ebay almost every day, so it’s a quite common lens.
The lens
Pentacon Electric 135mm/2.8 manufactured in a factory in Dresden, which was the former Carl Zeiss. A slim lens that are well built. It has a M42 screwmount that makes it easy to fit the EOS with an adapter. I guess you could find these on a Praktica-camera. The Electric version has zebra-type finish (like some Meyer and Zeiss also have). Early versions have close relation the Meyer equilant and more aperture-blades.
The resistance in the rings is ok in spite of a certain age. Sometimes apertureblades get stuck, but it is easily fixed through a little twist. The focus is very long to turn – this lens is not for fast focusing ;)
Thanks to the aperture ring sits closest to the camera, it is a bit difficult to see the scale because of the Canon EOS built-in flash, which shoots out over the aperture ring. There are of course only a compatibility problem, the lens and the camera was not made to fit together.
Testing
I’ve used this a lot from march to beginning of June 2008. It is supposed to be a great lens for portraits, but I’ve also used with success on landscapes. The best landscapes I’ve taken with this lens was in gray/blue days.
It is a sharp lens with good colour reproduction. According to information on the Internet, it has very good bokeh, I even saw the words “monster of bokeh” being used. It does have really good bokeh, but earlier versions of this lens is supposed to be even better.
135mm on my digital EOS-sensor with crop the focal length is 216mm, that is closer to tele (but not enough for tele, closeup birdphoto and the like, in my humble opinion… on the other hand I shot swallows with 50mm lens the other day).
I like this lens, but I like the Carl Zeiss Jena Sonnar 135mm better, with it’s fast focus and clear image. The Pentacons built in hood seems a bit fragile.
Images
Pros and cons
+ Sharp
+ Good colors
+ Good bokeh
+ Built-in lens hood (good against backlight of course)
- Long focus
- Sticky aperture on my copy (though I can live with that)
- As in many lenses EOS-flash sticks out over the aperture ring scale, making it difficult to adjust.
- Built-in lens hood (fragile feeling and awkward with filters)
Further reading








Pretty much agree wtih what you say but then my Pentacon is exactly the same as yours, and yes the earlier ones have better bokeh but they also have at least twice as many blades in the iris. I like this lens a lot but again it has a hard time competing with the CZJ 135mm/f3.5, which is slower but definately sharper. See if you can get the Pentacon 200mm F4 to try, that is probably my favourite of all the Pentacon lenses.
Yas I been on the lookout for a Pentacon 200/4. Still a bit mad about the one in mint condition I let go for £0.99 just becasue I wasn’t paying attention to the time :/ They seem to be quite common though.
By the way, I made some changes in the commenting here so from now on your comments should show direct and not end up in moderation que ;)
Thanks Mattias very kind of you. Some superb photos on the site btw catching a swallow in flight with a 50mm lens is quite an achievement!
Thanks :)
Beautiful samples, especially fogy lake! This is my favorite portrait lens I prefer before many others.
Thanks :) I like it to, when the aperture don’t stick ;)
The “bokeh monster” is used for an older version of the lens which has 15 blades iris. That lens gives a creamy bokeh of a perfect round shape.
While your lens is also good, it is not the “bokeh monster”.
@alexki-il: your right, it is the earlier version that has many blades :)