Posted: Sat Jan 05, 2013 9:11 pm Post subject: Carl Zeiss Jena Triotar 135mm f4 lens in Praktina on E-M5 |
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SXR_Mark wrote:
Carl Zeiss Jena Triotar 135mm f4 lens in Praktna mount tested on Olympus OM-D E-M5
Focal Length = 135mm
Max Aperture = F4
Min aperture = F22
Pre-set control with half stops between F4 and F11
Min Focus distance is under 1.2m (pretty good for a 135mm)
Optical scheme: Triplet, 3 lenses in 3 groups
Filter thread = 49mm
Mount = Praktina breechlock bayonet
Weight = 450g excluding caps
Length = 142mm unmounted without caps.
I won this lens in rough condition for £13.73 including delivery. Given the condition of the lens (very dirty and with fungus spots) this was hardly a bargain price. It could have been complete junk. These days, anything old with Zeiss on it commands a premium, even a tatty triplet lens in an obscure mount. Fortunately, the glass has cleaned up very well indeed with no detectable damage from the fungus and just a few very feint scratches on the front glass. The aluminium body has many surface scuffs but has polished up quite well. It looks better in reality than it does in the pictures below.
My homemade Praktina to micro-4/3 mount follows my normal practice of marrying the front of a teleconverter to a (in this case) L39 to m4/3 adapter, machining the two to get the correct overall length. I think the lens looks good on the E-M5.
The Triotar is a large lens. the filter rim is about 180mm from the image plane at infinity focus. Definitely not a telephoto lens! The size makes it handle quite well on the E-M5, though the equivalent focal length of 270mm means this is not a lens suited to hand holding.
You will find plenty of Triotar reports on this forum. Mine is possibly the first Praktina mount used on digital body (not that the mount will make any difference to the lens performance). It' is generally considered to be sharp for a triplet with good three-dimensional rendering.
Due to the horrible weather recently, I have not been able to test the lens thoroughly. From the tests I have been able to do I think sharpness is good but not exceptional at F4. It improves only very slightly at F5.6. One cannot expect super-sharp images from a triplet though. The key thing is that it does render very nicely. Contrast seems to be good as well (but note I used a good sized hood and shot with the sun behind me). Of course, a levels tweak helps but this can be said of almost any lens.
You can see subtle red and green halos around edges that are in front of and behind the point of focus, but these are not ugly or distracting. There is no obvious fringing at the focus.
All the following were taken at F4 with the camera mounted on a tripod
100% Crop from above, showing good but not outstanding sharpness.
100% Crop from above
100% Crop from above
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