Is Hasselblad gliding mirror system prevents vignetting really?

Is Hasselblad gliding mirror system prevents vignetting really?

Hello everybody.
Recently I had the chance to use a later version of the magnificent Hasselblad CF Tele APO-Tessar 500mm on my 503CW camera.
The lens is of later version that focuses down to 5 meter not to 8.5meters.
For the unexpected coincidence, the focusing screen has its upper border darkened!
Please see the photo attached.
AFAIK, 503CW camera has gliding mirror system that prevents vignetting in the viewfinder.
That's true for all my other CF/CFE/CFi lenses, long and short focal lengths.
Why my 503CW camera has this vignetting with this lens!?
I know it will not appear in the film, I did not yet tested for that!
but, whats going on?
Thanks for sharing your valuable milion cent opinion.

find duplicate lines

Most likely, you have much less vignetting in viewfinder than with some older bodys with no gliding mirror. Find somewhere 500 C/M to try it and you will be much happier with your 503 CW. I compared 250mm lens on 500C/M and on 2000CWF and difference was significant. Of course, on negatives, everything was OK.

I have the same thing with my 503 CW and 500mm CF lens. And yes, I was surprised as well.

I recently did a compare with a 250 Sonar on a 500C/M and a 501C/M. There was no vignette on the 501, and a thin dark band on the 500.

I have the Hasselblad 503 CX which does not have the Gliding Mirror System. Shortly after starting to use the camera with the 150mm and 250mm lenses, I stopped noticing the cutting off the top of the view finder. The camera has never cut off the top of the image on the film.

Thanks everybody
will see if I can test on another camera body if available and comeback.

Sirius Glass said:

I have the Hasselblad 503 CX which does not have the Gliding Mirror System. Shortly after starting to use the camera with the 150mm and 250mm lenses, I stopped noticing the cutting off the top of the view finder. The camera has never cut off the top of the image on the film.

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The mirror would only ever affect the image you see. It gets out of the way during the exposure.

The Gliding Mirror System (GMS) reduces vignetting in the view finder, it does not eliminate it. The longer the back focus, the larger the mirror has to be, and viewfinder vignetting happens on a lot of SLR's with long lenses.

Hassselblad literature from that period:

Gliding Mirror System (GMS) provides a full viewfinder image with virtually all lenses

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ie: not all lenses.

There are 3 mirror systems that are grouped in with the GMS name. The name was first used on the 503cw and 501cm, where the mirror slides out in from it's carriage as it lowers.

The other 2 systems predate these cameras. The entire F series (1600f ~ 202fa) has a compound mirror motion that is referred to as a GMS. The 500el series has a mirror that is on a short link that allows the mirror to flip forward when it descends. The extent that these 3 systems reduce vignetting is probably different. The F series probably has the best performance. I don't believe Hasselblad literature ever referred to these as GMS, but sales people did as the mirror systems had the same effect.

(PS: prior to the 500cw, the mirrors on the F and EL series were described as "non-vignetting")

I think it is because the rear element is farther up in the lens that even a gliding mirror camera like the 500ELX, 501CM and 503CW will still have the dark band on top.

I now know this as of tonight in having received my new CFe 350mm Tele-Superachromat and the Apo 1.4XE converter. I was pretty surprised to see it on my 501 CM because not even my 350mm CF does it, but its rear element is almost an inch closer to the film plane than the Superachromat. It’s not bad with the 350 by it self but it’s quite a bit with the 1.4X on, I would say a bit worse than the photo you have shown.

I’ll just have to make sure to use it with a grid screen to frame precisely.

Otherwise it is a truly spectacular lens, easily holding up to a 100MP sensor.

Ai Print said:

I think it is because the rear element is farther up in the lens that even a gliding mirror camera like the 500ELX, 501CM and 503CW will still have the dark band on top.

…

I’ll just have to make sure to use it with a grid screen to frame precisely.

Click to expand...

If this is a mirror issue, it will have no impact on your image on film, and is simply cutting off in the viewfinder.

OTOH, if you are getting cutoff (lens not covering the film area, which I doubt) then sure, you would need to keep it in mind when composing.

Eff64 said:

If this is a mirror issue, it will have no impact on your image on film, and is simply cutting off in the viewfinder.

OTOH, if you are getting cutoff (lens not covering the film area, which I doubt) then sure, you would need to keep it in mind when composing.

Click to expand...

The problem is entirely in the mirror area. After a short time I stopped noticing it with the 150mm, 250mm and 500mm lenses.

Eff64 said:

If this is a mirror issue, it will have no impact on your image on film, and is simply cutting off in the viewfinder.

OTOH, if you are getting cutoff (lens not covering the film area, which I doubt) then sure, you would need to keep it in mind when composing.

Click to expand...

It’s only the view / mirror. I can work around it by cheating up a bit to check image content and then scrub back down according to the place on the grid lines.

Framing is super important to me so I can’t just let er’ rip unchecked.

2000 FCW and Sonnar 250mm



500 C/M and Sonnar 250mm