Mamiya RB 90mm lens.. unimpressed?

[Nicholas Lindan]

Perhaps I need to check the focus registration on the camera.. Here is an example, with a cropped section.

The girl in front is in sharp focus, extending to her near arm. The far girl is beyond the DOF of the lens. I don't know where you focused the camera - if it was for the average of the two girls faces then your camera is a bit off and focusing closer than it appears in the finder. The screen needs to be shimmed up; the problem can also be the rest position of the mirror is higher than it should be.

As to contrast - looks OK, it's just that the shot is a 1/2 stop or so overexposed. It would have been better to stop down to more properly expose the background and use a reflector to light the girls' faces. I have taken to carrying a small collapsible reflector with me. Windshield sun screens make a very cost-effective reflector, they twist up the same way the photographic reflectors do.

 

[Shadowtracker]

Nickolas, I was going to say something similar to this - but for me, it's the eyes. The point of focus is not on the eyes which I think makes a difference. If you can, find a copy of Barry Thornton's "Edge of Darkness" I'm sure there are similar test, but all you have to do is print out or make a white board with vertical lines on it. On the center line, draw > < one on top, one on bottom, so you know which line is the center one. Then set up the camera at a known - read that Measured, distance. Set the card or board up so the center line is at that distance and inclined with one end closer to you and the other further away. Then focus the camera on the center line, develop the negs, make a print from them. The lines, being something like 1cm apart, will tell you if your point of focus on your camera is on, long or short. From there you can adjust the camera or your focus, whichever one you want. It did wonders for helping me understand why I was getting 'slightly off' photos for a while. Since doing this, I did shim the screen and now I tend to get pretty sharp images.

 

[Athiril]

All my C's were fantastic, lost my 90 C :'(, still got and use my 180C and 65C, love them, they're brilliant.

Inspect the lens elements by holding up to light, see if any has an oily coating or something etc, that can be easy to miss.

 

[Chuck_P]

I had an RB with a 180 and a 90, both non-c lenses and loved them, no problems------but sold it to move into LF, which brings me to my next thought------last I checked,the RB and its lenses are a MF camera system-----this is the LF forum. Just a curious observation.

 

[tk6411]

Its common for many new to the RB67 to forget or not know about the floating optical adjustment on many of the RB lenses. Without adjusting the floating element at the front of the lens to compensate for the distance of the subject many RB lenses will be soft to those unfamiliar with the RB system who forget to adjust the lens. Properly adjusted it will be sharp, assuming everything is in focus. You must adjust the floating element for each subject at varrying distances.

Jim

 

[tim elder]

Is the "C" model any different?

The C models have a different, more modern multi-coating than the non-C lenses and are generally considered superior for color film.

Tim

 

[CBG]

The RB generally has very good glass. If you have a sharpness problem, you either have lenses that are way off specs or were dropped when shipped etc or your focusing screen is not installed within specs.

 

[Ric Trexell]

The best thing is to have a repair place look at it through a collimator. If the image on that is sharp, then it is a problem in the viewfinder. It does appear to be a little soft. That would be great for older women, but not young gals. Ric.

 

[paul ron]

Is the lens clear or slightly hazed or dusty or dirty? Does the focus on the film plane agree with the viewfinder? Use a lens hood? Need more info n trouble shooting here, because RB lenses are generally very sharp.

 

[epatsellis]

To get an idea of how sharp, I use my Dicomed back on my RB, I get 6k x 6k images that are frighteningly sharp, they do really well on film, and really show their strengths with digital backs as well.

 

[photoncatcher]

I've been shooting with the RB67 since the 70s, and I've rarely seen such good glass. Some of my negs have gone to 16x20 with no loss of sharpness, or contrast. I do agree with Terry about the tripod, and dual cable release. The RB can be a beast to hand hold.

 

[rulnacco]

I've got a 90mm C lens, and it's pretty darned sharp. Back when I first got it, I took a full length portrait of a fellow of slightly above average height, leaving a bit of room at both the top and bottom of the frame. Under my 4X loupe, I could clearly read the writing embossed on the button holding up his jeans--it was absolutely sharp and defined.

I would be quite pleased to know my 35mm lenses are producing such resolution and definition on an equivalent area of film. Medium format lenses generally don't need nor boast resolution as high as lenses for smaller formats, as less magnification is required for the same print size. But my 90 seems to have just as high resolution as the top-of-the-line Nikon lenses I own. With that, I am absolutely satisfied.

 

[chassis]

Overall a nice image, with some comments:

- I see flare in the image from the angle the camera is facing the sun.
- The two subjects are at different distances from the camera. At f/5.6 this will mean difference in focus.
- The faces are in shadow, which may not create a sharp looking image.

Shoot a few rolls in different lighting conditions and see if you feel the same way about the lens.

 

[James Bleifus]

I only have the 90mm non-C lens on the Mamiya RB 67.
Frankly, I'm unimpressed by it.

Unfortunately, I feel the same. Today I developed the first rolls of film from my newly purchased RB67 with a 90mm non-C lens and was very disappointed. It didn't match the sharpness or contrast of my Bronnie ETRS 75mm MC lens. That means the whole kit is going back to KEH. I love the feel of the RB over the Bronnie, but the quality of the images comes first. I know others are very fond of their 90s so I'm guessing mine has some problems.

Cheers, James

 

[Citizen_Erased]

I've never had a problem with sharpness on my 90mm C. I've blown negatives up to 20x24 without any loss in quality and that's from me using it handheld. Though, this was in the middle of the day, with full sun, but I stopped the lens down to f/11 to give me more depth of field and bring out detail in my subject. I've found that shooting wide open is kinda sketch because you need to be dead on with your focus.