doubs43
Well-known
This past weekend I did some testing - unscientific, to be sure - of my four 135mm LTM lenses: a Black Hektor, a Silver Hektor, a Canon & a Komura. My purpose was to check rangefinder focusing accuracy at close distances. Knowing exactly what each lens will do at close range is important. At roughly 9 feet I took a series of three shots with each lens on EFKE-25 film developed in Rodinal 1:25. Each negative was scanned at 3200 dpi and the sections you see were cropped from the full scan. Absolutely NO manipulation of any kind has been used.
The two best lens on my Bessa-T appear to be the 135mm F/4.5 Black Hektor and the Canon. Results are so close as to be thought of as identical. One might even give the Canon a slight edge because it at least matches the slightly slower Hektor at the wider aperture of f/3.5.
The Silver Hektor and the Komura both show best sharpness in front of the focal point by a number of inches. Their cams are not matched to the Bessa-T rangefinder as well as the other two lenses.
I'll shortly post similar tests on the same four lenses plus two 90mm Elmars mounted on my Leica IIIc.
The scans seen here are - in order - Black Hektor @ f/4.5; Canon @ f/3.5; Black Hektor @ f/8 & Canon @ f/8.
Walker
The two best lens on my Bessa-T appear to be the 135mm F/4.5 Black Hektor and the Canon. Results are so close as to be thought of as identical. One might even give the Canon a slight edge because it at least matches the slightly slower Hektor at the wider aperture of f/3.5.
The Silver Hektor and the Komura both show best sharpness in front of the focal point by a number of inches. Their cams are not matched to the Bessa-T rangefinder as well as the other two lenses.
I'll shortly post similar tests on the same four lenses plus two 90mm Elmars mounted on my Leica IIIc.
The scans seen here are - in order - Black Hektor @ f/4.5; Canon @ f/3.5; Black Hektor @ f/8 & Canon @ f/8.
Walker
Interesting comparison, Walker... At both apertures tested the Hektor appears to have better contrast, though not better sharpness. I'm most surprised by the radically different appearance of the (grass stems?) background in the f/8 shots.
doubs43
Well-known
Doug said:
Doug, thanks for taking the time to compare. The difference is likely caused by the Hektor having more "front focus" while the Canon has more "back focus". I was careful to focus on exactly the same point on the can for each shot and three of the four lenses show greater depth of field (sharpness) in front of the can than the Canon which shows more dof behind the can. IMO, the Canon is closer to being "right on" than the other three and will likely be my lens of choice for the Bessa-T in 135mm.
I repeated the tests with my IIIc and I'll post those results very soon. They're similar but different.
Walker
back alley
IMAGES
were the hektors made prior to the canons?
i would have thought that contrast would have been closer.
joe
i would have thought that contrast would have been closer.
joe
doubs43
Well-known
backalley photo said:
Joe, the Black Hektor is coated and a 1946 vintage while the Silver Hektor is from 1953. I have no idea how old the Canon lens is but the serial number is 68813 and it's all black - except the silver colored mount - with click-stop aperture values. I'd guess that it's close in age to the Silver Hektor. The age of the Komura is anyone's guess.
The scans are exactly as they came from the scanner at 3200 dpi. I didn't manipulate them in any fashion at all. Optically, all four lenses appear to be in superb condition.
Walker
back alley
IMAGES
for the canon...
Approx date issued:
4/58 to 12/60
Serial # range:
66052 to 73921
Approx date issued:
4/58 to 12/60
Serial # range:
66052 to 73921
doubs43
Well-known
Joe, thanks for the information. I didn't know. Is your Canon source a book?
Walker
Walker