SMC Pentax 67 75mm f/2.8 A not that good

[fastw]

Bought a mint one mainly for close up portraits, so I needed really sharp images. After the first roll I was somewhat disappointed as the images weren't that sharp. Tried another roll and pretty much the same results. Decided to do a proper comparison with my old $88 135mm macro that I've used for a couple of years and really liked the results. You can see on attached images how much sharper and more contrasty the old macro is. Managed to return the 75 without any problems, John from Camera Exchange in Melbourne is the the nicest guy I've ever dealt with.
Bit disappointed and will have to go back to the old work horse for next India trip.
Cheers, Wojtek.

 

[Angelo di Mango]

Sorry about your experience but this is rather unusual as this lens is highly sought for therefore it must be true to its reputation!
Perhaps a CLA might help even if the glass does look clear something might be ill adjusted. hope that will help.

 

[polyglot]

Any chance you have a focusing issue? A shorter lens will show errors due to ground-glass/mirror/back misalignment much more dramatically than a longer lens.

 

[fastw]

There would've been enough DOF in that shot even with a bit of a focus problem. Anyway, it wasn't what I expected. I really wanted it to work.

 

[Arvee]

Looks like more of a contrast issue than a resolution issue. Shine a flashlight through the lens and check for haze, fungus, dust. A CLA might be in order here.

 

[Poisson Du Jour]

What!? A CLA for a hallowed, top-level SMCP lens? No, not likely at all. You say you bought this lens mint. If this lens had a fault, especially with the glass, John would have noted it and graded it accordingly. Very little escapes his attention when dealing with professional-level equipment and that's what this lens is. There are a number of APUG members who use this lens and swear by it. And rightly so.

I bought my 75mm f2.8AL mint from John at Camera Exchange too, and I can tell you it is the finest lens I have used so far, just slightly ahead of my other two "golden oldies" (ancient Distagon designs) — the SMC Pentax 45mm f4 and the SMC Pentax 55mm f4. There are no chroma or sharpness problems in normal use; there is barrel distortion (it is not a rectilinear lens: if it were it would cost several times more). Moreover, contrary to common application, the 75 AL is not a macro lens or even a close-focus lens in the strictest sense, although it does get surprisingly close for this focal length. The sample images you have posted tell me nothing other than you are too close or have used a deep aperture and introduced diffraction that, despite the lens design, will not get you out of trouble. Another potential problem: focusing screen calibration. After 10 years of constant use, the 6x7 / 67 focusing screen should be reset with a collometer to establish true infinity focus (matt area and 2 points in the central prism). If you are using a macro lens, a focusing fault will not be pronounced with either lens. Critical focusing of subjects at infinity and examination of the results with an 8x loupé on a lightbox will establish if there is a fault like this.

This is a sample image of the 75AL at work (shot at f11). Don't be concerned about a perceived lack of sharpness in this image — it's a quick scan for client briefing. The transparency is in-process for printing quite large at the time of posting this.

 

[fastw]

PDJ, I actually used a 55 for the comparison as well. It placed in between, closer to 135. Focusing was not an issue with other lenses and BTW, portraits taken with the 75 look quite sharp, just not as sharp as I expected. Most users would probably be pretty happy with it. Your image looks great, but it's only small. OTAH maybe it's for the best, as I think it's a bit too wide for what I'm doing. BTW , why am I too close, the 55 was even closer. Aperture was F8 on all three if I remember correctly.
Listen, maybe it's just a poorer example of this lens, I also read nothing, but praise for it.
Doesn't matter, I'm off to India to continue my project and can't wait to go.

Cheers, Wojtek.

 

[sbjornda]

What body are you using this on? 75mm on a 6x7 is wide angle, not a portrait lens. Also, one usually doesn't want too sharp a lens for portraits (too sharp makes blemishes and wrinkles stand out).

 

[fastw]

I'm using a 67, and as far as I'm concerned, any lens can be a portrait lens. I look for wrinkles and blow my prints up to A0, so you can see everything. Just like big, detailed portraits.

Cheers, Wojtek.