Mamiya RB67 Pro S DOF

[dustym]

Can anybody tell me how to operate the DOF on the 90mm On the RB 67
PRO s is it just as simple as reading the side scale and replicating it on the lens. I do have a manual but it is th SD

Any help would be appreciated



rgds
Dusty

 

[Sinarfar]

Hi Dusty,

The DOF scale on the lens is just that, a scale. It will show you the DOF for a given focus point and stop. The focus is set on the camera body scale. Of course you can always stop down to check DOF.

Hope this helps.

 

[waynecrider]

Don't you have a stop down lever on the lens itself? I do on my 127mm and it's far easier for me to see dof (to a certain point) then to judge to a certain distance based off the top scale on the lens. If you really need some sort of DOF or hypperfocal method printout here's one you can fill in with your data to get any distance you would want or your hyperfocal distance. Dead Link Removed The scale on the side of the camera is a exposure compensation guide for bellows extension.

 

[rogueish]

Set your focus on the object. Turn the DoF slider (on the lens), so that the distance (taken from the side of the camera)on the scale is on the red mark (center of scale). Your DoF will then be shown as to what aperature your using.
For example, if your using f8 and the distance is to the object is 3 feet (.9m), then your DoF will be just over 2.75 feet, to about 3.25 feet. If using f22, and your focus is 5 feet, then your DoF will be just under 4 feet , up to just over 7 feet.

Ok now that I actually re-read your post :rolleyes: , yes it is as simple as reading the side scale, then replicating it on the lens.

 

[Troy Hamon]

An observation from another RB shooter...the DOF scale on the lens has a much less stringent standard for what is 'in focus' than I do. They appear to have used a larger circle of confusion for the calculations than what the lenses are capable of resolving. As a result, if I set the focus based on the depth of field from the slider and the lens guide, I still get very soft focus at the near and far end. My understanding from previous threads on other fora (language alert! plural for forum!) is that this is a common malady with other medium format cameras as well. My recommendation, based on my own experience, is to use the depth of field preview, not the scales. If you are not printing larger than 4x5 the distinction may not be important. Good luck.

 

[rogueish]

My recommendation, based on my own experience, is to use the depth of field preview.

Unfortunately, the 90 lens for the Mamiya RB does not have the DoF preview option. I know the 150 and the 250 do , but not my 90. Don't know why.

 

[Troy Hamon]

Mine does...I have the C version. Perhaps a difference with the pre-C? Not sure.

 

[dalahorse]

Mine does...I have the C version. Perhaps a difference with the pre-C? Not sure.

The older pre-C 90mm does have DOF preview. When the lens is mounted on the camera, the lever is very close to the shutter release button on the body.

 

[Drew B.]

ok for all the RB/Rz users, I'm putting together a system...have the RZ body, viewfinder, 120 back...but not a lens yet. I'm somewhat confused by the manual, so, my question is: the lens doesn't have a focusing knob?? I thought the knobs on the body were for the bellows only which I thought was for close up photography. Can anyone tell me how this system works? I do architectural work, will mostly use shift and wide angle lenses and will use rather slow shutter speeds....from 1/16 to a minute or so. Did I buy the wrong system?

drew

 

[Elox]

All focusing is done with the bellows, via the knobs on the body. See:

medfmt.8k.com/mf/mamiyarb67.html

This has some basic info and lots of comments. I just disagree with the comments about the RB/RZ being mostly a studio camera.

 

[rogueish]

Mine does...I have the C version. Perhaps a difference with the pre-C? Not sure.

All my lens are C models. I have the slider for the scale, but no DoF. Really isn't a problem, but you could be on the right track. An early model in the C line?

 

[rogueish]

so, my question is: the lens doesn't have a focusing knob?? I thought the knobs on the body were for the bellows only which I thought was for close up photography.
drew

Yes the knobs on the camera body are for focusing. No the lens has no focus mechinism (They do have a DoF preview though). To the best of my knowledge, there is no tilt\shift to the camera itself. I also didn't know you could get shift lens for the Mamiyas.