The Leica Hektor 135mm f/4.5 is probably the least expensive Leica M lens available today - it sells for $50-$300 on eBay or the used departments of B&H, Adorama and KEH. Leica manufactured this lens between 1933-1960. The serial number of mine revealed that it is produced back in 1958. The Hektor model was replaced in 1960 by the Leica Elmar 135mm f/4. Lenses with serial numbers from 1,124,000 - 1,416,000 have a 36mm filter thread; serial numbers from 1,416,000 - 1,827,000 have a 39mm filter thread. All versions produced after the WWII were coated. The aperture has 15 blades and a range of f/4.5 - f/32. The 135mm Hektor has 4 lens elements in 3 lens groups. The angle of view is 18° and the minimum focusing distance is 1.5m/5 feet.
The exact label of the lens is Ernst Leitz GmbH Weltzlar Hector f=13.5cm 1:4.5:
The lens has its own tripod mount for better balance:
The focusing ring on my copy is rather firm and can be rotated at approximately 340°. This could be helpful for getting a precise focus, but slows down the process since there is more rotation involved. For better focusing, I used this lens with the 1.25x viewfinder magnifier. The lens hood is reversible and the lens cap can fit on top of it:
The distance scale of my version was only in feet:
This is the obstruction of the lens in the viewfinder of the M9 with the lens hood on (without a viewfinder magnifier):
The Leica M9 doesn't have a dedicated manual lens setting for this lens. The closest selection is the 135mm f/4 (11851/11861):
Compared to the modern Leica lenses, the colors produced by the Hektor 135mm f/4.5 are not as saturated and vibrant (compared to the latest Summarit-M 90mm f/2.5 lens):
The examples below were taken from the center of a test chart. From what I can see, the maximum sharpness is achieved at around f/5.6-8 and then stays constant all the way up to f/16 (look at the small digits for better comparison):
f/5.6 (compared again with the Summarit-M 90mm f/2.5 lens)
f/8 (second image from the Summarit-M 90mm f/2.5 lens for comparison)
Please note that there could be a margin of error in those test chart comparisons. Here is a real world 100% crop taken at f/8:
When shooting with the 135mm Hektor lens wide open, I could not see any vignetting or barrel distortion:
Lens flare is strongly pronounced even when the lens is not directly pointed at a light source and the lens hood is on:
The 135mm Hektor is not a fast lens and is probably not a good idea to use it in low light, but you can still get out of focus background when shooting wide open (f/4.5):
Here are some sample images taken with the Hektor 135mm f/4.5 lens and Leica M9 at the Miami marathon (images were not post-processed, just directly converted from DNG->JPG in Lightroom 3):
Higher resolution are available on flickr.
The drawbacks of this lens is the lack of sharpness, dull colors and pronounced lens flare. For a 50+ years old lens with a price of $50+, I am willing to ignore all those weaknesses. For the rare occasion that you may want to use a 135mm focal length on a Leica M camera, this lens is a cheap alternative to the latest Leica 135mm f/3.4 APO-Telyt-M model which sells for $3,295.00.