RB67 this confirms focus a bit off? 180mm KL lens on original body?

[rayonline_nz]

Hi all

In the past I have shot F11 landscapes and they are in focus however I had issues with portraiture at say F5.6 I think with the 180mm. When I look at the original slide film on the lightbox it's not in focus compared to my landscape shots - landscapes some shot also with the 180mm lens at F11.

So today ... my older original RB67 unfortunately need bellow replacements and no one in my country can source bellows. Anyway it has a split screen focus screen, I pop that into my Pro SD RB67 body with the 180mm I focussed to some distant hills / houses. When I focussed to infinity the split screen was still not perfectly aligned. It was like if I needed to go pass the infinity mark but obviously the camera won't let me do that. So is it just the ground glass not needs calibration or could it be something else?


Also ever since I got my 180mm KL lens I've only used it on my Pro SD body. Today with the original RB67 I could not attach it on but the 127mm KL lens does fit. I've attached a photograph here. The 180mm has a fixed in not removable hard rubber / plastic.

 

[MattKing]

That hard rubber/plastic ring looks like the removable collar designed to improve use of the older lenses on the Pro SD body (which has a wider throat in order to permit use of the 75mm shift lens).
http://www.reznitsky.info/Mamiya/Comchart.htm

 

[shutterfinger]

Focus issue: Being this is a reflex camera put a piece of ground glass at the film plane with the shutter open, lens aperture wide open and focus infinity on a target at least 5000 feet/1524 meters away (the further the better) then compare to the view screen. Use a good loupe on both. If the view screen does not agree with the gg then verify that the reflex mirror is returning to its correct position, repair as needed, and if good shim/adjust the view screen to agree with the gg.

 

[wiltw]

To summarize what you said (to make sure I got it all straight):

1. Your Body A is RB67, your Body B is RB67 Pro SD
2. You took focus screent out of body A and put it into body B
3. You mounted a 180mm lens from body A onto body B
4. Things are not in focus with the 180mm lens, and this is true of both body A and of body B

Assessment:

1. What could be wrong is the reflex mirror is not resting properly, but that is highly unlikely to affect both body A and body B
2. What could be wrong is that the 180mm lens is somehow not in focus on both bodies, leading me to suspect the lens.
3. But the lens does not have its own focus mechanism...it is like a view camera lens, the focus is handled entirely by the bellows and rail of the camera! But if something screwed up the internal lens element positioning, that could throw off the fundamental optics and focus point of the lens.

The suggestion to put a ground glass on the film rails at the focal plane is a good way to comfirm that the actual film plane focus point is matched by the reflex mirror to focus screen focus point.

 

[rayonline_nz]

Steps 1 and 2 - correct. Step 3, no the 180mm I have only used on Body B. Step 4, cannot verify body A because I used electrical tape glue onto the broken bellows and it has made it too thick therefore the bellows cannot retract fully and focus to infinity.

 

[MattKing]

Step 4, cannot verify body A because I used electrical tape glue onto the broken bellows and it has made it too thick therefore the bellows cannot retract fully and focus to infinity.

So the body and lens are probably fine - the problem arises because of the attempt at repair.
Essentially it is as if you added an extension tube.

 

[rayonline_nz]

So the body and lens are probably fine - the problem arises because of the attempt at repair.
Essentially it is as if you added an extension tube.

Not so quick. The mint condition Pro SD (body B) which I have used in the last 6 months I am still unable to have a real in focus portrait. 1.5m person away from camera, RB67 Pro SD, 180mm lens prob at a F5.6. Shot on tripod as well, shutter speed prob 1/125 or 1/250. I have not used the body A body recently since I got body B.

Body A is the original RB67 with the failed repair - used from 6 months ago.
Body B is the mint condition RB67 Pro SD. Used recently.

All I did was borrow the split screen from body A and used it in body B. I did so b/c the split screen might be a bit more accurate for focussing. In the past with my body B with it's non split screen I couldn't get my portraiture in focus.

 

[cramej]

1. The ring is removable. It is aluminum and unthreaded.
2. Focusing screens are adjustable so they cannot just be swapped from body to body.
3. It is likely that the old screen on Body B was not adjusted properly. Now you have a different screen on it that's still not adjusted properly.

4. Focus issue: Being this is a reflex camera put a piece of ground glass at the film plane with the shutter open, lens aperture wide open and focus infinity on a target at least 5000 feet/1524 meters away (the further the better) then compare to the view screen. Use a good loupe on both. If the view screen does not agree with the gg then verify that the reflex mirror is returning to its correct position, repair as needed, and if good shim/adjust the view screen to agree with the gg.

 

[rayonline_nz]

Thanks for that.

I will have another look at that ring.
Looks like I need the camera to be adjusted.


Re: Body B. It is a frankenstein set-up. Pro SD body, Pro-S revolving adapter and Pro-S film back that was how it was delivered to me. The focus screen is also an interesting one that you guys may had seen in the past. It does say Mamiya No. 7 on the side.




Re: Body A much more worn, well it was cheap ie $105US with an original Pro Non S body, Non-S revolving adapter and a Non-S film back and a non C 90mm. Funny enough he sent me a Pro SD users manual. Perhaps he had 2 bodies and he sold off his more worn setup.

 

[shutterfinger]

Optical distance from subject to image on the view screen must equal the optical distance from the subject to the film plane. The film plane image is the reference for adjusting the view screen.