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Thread: Hasselblad RM-2 Viewfinder Modification (for 203FE)

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    Hasselblad RM-2 Viewfinder Modification (for 203FE)

    In the recent CFV-39 thread, possible issues were raised around compatibility of the various 90-degree finders and the CFV back.

    With respect to CFV compatibility and PM90 and PME90 viewfinders, some have said they do work with the 503 body, while others have indicated they will or might not. I don't have a CFV back so I can't say much of anything to help.

    I did purchase an RM-2 (an HC-3/70 finder with a larger exit pupil and lower magnification) with the intent to modify it to work with the 203FE. Due to its design there is no risk of interference with a CFV back, but it was not designed to slide over the 203FE's viewfinder LCD display.

    I did perform the modification, and I'm pleased to say that it works! Mostly. (See below). All said and done, the cost was $3 and a couple of hours.

    Here are photographs of the process of modifying the RM-2 in a minimally invasive way. By doing it in this way, the viewfinder lacks the 'snap' it had on the 500-series I tested on previously. It does partially obstruct the LCD (I cannot tell if this is due to my modification or because the initial design does not allow for the LCD display). At some point in the future I will probably have the front edge of the viewfinder ground 1.5mm to accomodate the LCD without using standoffs (see below):

    (Please excuse the poor quality iPhone photos.)


    This is the base of the RM-2. Note the silver ring goes all the way around. The front of the viewfinder is at the bottom of this photo, and would collide with the LCD screen on a 203FE.


    After measuring the size of the gap using another finder (see next photo) it was very easy to remove and cut through the finder ring. This is the only permanent modification to the finder. I assume it will not be too much trouble to purchase a replacement ring to restore the finder to stock, if necessary. Even if not, the cut won't change the finder's performance on a non-LCD Hasselblad.


    Comparison to the gap of a PME-51 45-degree finder (bottom), which *is* compatible with the 203 FE. A perfect match. Attempting to fit the modified RM-2 finder to the 203FE revealed that an additional ~1.5mm of clearance is required. Note the cutout in the front of the housing of the PME-51.


    Instead of making the same cutout in the housing of the RM-2, I decided to use a standoff to raise the housing off the ring by about 1.5mm. It was pretty easy to do with some adhesive felt and an X-acto knife. This felt comes in rectangular pads for $3 from Home Depot. I still have $2.50 worth of it left over.


    The ring is reattached to the finder and slid partway onto the 203FE. Clearance over the LCD (that white bar between the 'Hasselblad's) looks good!


    Success! Works like a charm.


    Any issues? Well, yes, actually. The finder doesn't 'snap' into focus like it did before it was raised. I'd assumed I could compensate for this easily with the diopter adjustment at the eyepiece of the RM-2, but despite a huge diopter range, it doesn't ever get as crisp as it did before I raised it. Based on that, I have to recommend grinding out the front 1.5mm for best results. Still, it's useable for now, and I'll eventually explore the PM-90 as an option before griding, assuming the CFV-39 lives up to expectations.


    A little low fidelity camera pr0n for those still reading. (Forgive the atrocious fashion clash of a black body and a chrome back! hahaha! I've borrowed a film back from a friend to see if I like the handling enough to finish the job and go digital with this kit.)


    Here's the 203FE with the Hasselblad-modified Winder CW attached.

    Best regards,
    -Brad

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    Re: Hasselblad RM-2 Viewfinder Modification (for 203FE)

    Wow. Nice write-up, Brad. Thank you!

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    tetsrfun
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    Smile Re: Hasselblad RM-2 Viewfinder Modification (for 203FE)

    Great series of pictures and explanation. My guess is you won't be happy with the 1.5 mm elevation and slight alteration in focus. I was never quite happy with my ability to always get accurate focus with a PME-45, 2.5x mag. and a CFV. With a CFV39, I suspect that focus will be even more critical but nothing to loose by trying it before the getting out the grinder.

    I think your project will help a lot of people. I think the CFV39 is going to be popular and the HC-3s and RM-2s seem to be disappearing from the used market.

    Steve

    BTW.. love the look of the CW winder on the 203..

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    Re: Hasselblad RM-2 Viewfinder Modification (for 203FE)

    Thank you Brad for your detailed rework report .
    I was looking forward to hear your experience and after reading your report twice , I decided NOT to rework my RM-2 viewer .

    An other interesting fact is your 503 winder attached to your 203FE .
    I have also an F-Winder but am not very happy with it . The 503 winder is better in my hands .
    Who made the modification ? ? ?
    I can remember , that I read something about that topic .
    If you can lead me to that info , that would be nice .
    Thank you .

    Jürgen

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    Re: Hasselblad RM-2 Viewfinder Modification (for 203FE)

    You're welcome, guys.

    I think not doing this is probably the right answer, unless you're prepared to grind the front of the housing (more work). With the 'easy route' I took, the resulting quality through the viewfinder just isn't as crisp as it should be (I'd like to see the LCD too--perhaps grinding the housing would permit this, but I do not know). Still, this will do for now, for me, but I think I will continue to look for a better solution.

    As for the winder, let me start with the downsides--it's heavy, and it's noisy. But you already knew that... On the upside, wow, what a difference it makes to handling the camera!! I feel you get the best of both worlds with this, as you can use the crank when you need to save weight or be quiet; and you can use the handle when you want convenient handling (particularly with a 90 degree finder, which is much more necessary on a camera whose rectangular back doesn't rotate).

    Just so you're aware, using the ergonomic winder means you're adjusting your exposure with your left hand, and most Hasselblad lenses are designed to be operated with the right hand. You have to adapt a bit, looking for a good place to grab the aperture ring.

    Who modified the winder? Hasselblad did, for their Space Camera program. Mine was difficult to get. I found a contact within NASA and got to the folks who could help me get one of these, but NASA doesn't sell their stuff. I contacted Hasselblad about getting one, but they don't sell these; and were unwilling to release schematics, etc... I managed to find a private seller in Europe who was selling one (no idea how he got it).

    The handle on the 203FE is a big deal for me--I don't think the camera would be as viable for me without it. Of course, YMMV.

    Other options:
    DIY instructions to modify a winder: http://translate.google.com/translate?prev=hp&hl=en&js=y&u=http%3A%2F%2Fforum. xitek.com%2Fshowarchives.php%3Fthreadid%3D378471&s l=zh-CN&tl=en&history_state0= (autotranslated from Chinese).

    Another method--modify your camera to accept an unmodified winder: http://www.flickr.com/groups/hasselb...7620589093938/.

    Best regards,
    -Brad

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    Re: Hasselblad RM-2 Viewfinder Modification (for 203FE)

    I was very puzzled as to why adding a bit of offset to the finder housing would cause the resulting image to lack snap and be generally soft.

    So I did a bit of experimenting and put the modified finder on a 500C/M and found the view through it to be perfect.

    I then swapped focusing screens (default 500C/M with default 203FE), and lo and behold! The modified finder on the 203 has all the sharpness and snap that it should! (It is probably worth noting that the RM-2 isn't a great finder in terms of sharpness outside of the central area, but this was the case before the modificaton).

    I wasn't able to mount the unmodified RM-2 finder on the 203FE, but I suspect I would have found that even before I modified it, the image would have been unsatisfactory.

    Note that the PME-51 looks just fine when used with either screen, so there is some interesting optical incompatibility problem between the RM-2 and the 203FE's default focusing screen.

    So to summarize, this modification turns out to work just fine, as I had originally hoped, and I can now recommend it without reservation. If you are shooting a 203FE, you will want to replace the default focusing screen when using this viewfinder, as the image isn't satisfactory with it (even if the finder did fit unmodified).

    -Brad
    Last edited by BradleyGibson; 23rd July 2009 at 18:21.

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    Senior Member PSon's Avatar
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    Re: Hasselblad RM-2 Viewfinder Modification (for 203FE)

    Excellent finding Bradly!
    -Son

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    tetsrfun
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    Re: Hasselblad RM-2 Viewfinder Modification (for 203FE)

    I then swapped focusing screens (default 500C/M with default 203FE), and lo and behold!
    ********
    That is interesting...After reading this...I tried RM-2 and HC-3 with different screens. No 203FE, sorry to say, but a 503 and ELM. The older screen wasn't very good but both were good, edge to edge with the latest Acute-Matte D screens.

    Steve

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    Re: Hasselblad RM-2 Viewfinder Modification (for 203FE)

    Thanks, Son!

    Steve, yes, it's weird. I wish i knew which screens I have by model #, but the RM-2 doesn't even get the screen markings really crisp on the 203FE's default screen (even if they're both mounted in the 500C/M). I can only conclude that they don't like each other for some reason.

    Likewise, the 500C/M's default screen looks just fine with the RM-2 on either body, so I know the bodies themselves aren't the problem. Screens are easy to deal with--assuming I stay with this platform, I plan to give Mr. Maxwell a call anyway for a custom screen... Now that I know the RM-2 is working, I'm happy!

    Next step is the digital mod for the 203FE, followed by a CFV39 test drive... Stay tuned!

    -Brad

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    Re: Hasselblad RM-2 Viewfinder Modification (for 203FE)

    I swear to God, you need to try the PM45 before thowing in the towel if you can't make this work. The adapted CW winder makes it a really viable way of shooting portrait oriented shots ... sounds like it wouldn't until you actually try it.

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    Re: Hasselblad RM-2 Viewfinder Modification (for 203FE)

    Quote Originally Posted by fotografz View Post
    I swear to God, you need to try the PM45 before thowing in the towel if you can't make this work. The adapted CW winder makes it a really viable way of shooting portrait oriented shots ... sounds like it wouldn't until you actually try it.
    Interesting, Marc. Is that what you use for portrait mode with the CFV? I would have that the angle would be strange, but I guess not.

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    Re: Hasselblad RM-2 Viewfinder Modification (for 203FE)

    Quote Originally Posted by fotografz View Post
    I swear to God, you need to try the PM45 before thowing in the towel if you can't make this work. The adapted CW winder makes it a really viable way of shooting portrait oriented shots ... sounds like it wouldn't until you actually try it.
    Thanks, Marc, but um... Check the post #6--I did get it to work...

    And the PME51 I've been using is a 45-degree finder (odd name, I know ). I like it too, but the magnification is lower than the RM-2, and using 45 degree finders with the body in portrait orientation (required, with the CFV-39) is awkward, well, for me at least.

    -Brad

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    Re: Hasselblad RM-2 Viewfinder Modification (for 203FE)

    Quote Originally Posted by BradleyGibson View Post
    Thanks, Marc, but um... Check the post #6--I did get it to work...

    And the PME51 I've been using is a 45-degree finder (odd name, I know ). I like it too, but the magnification is lower than the RM-2, and using 45 degree finders with the body in portrait orientation (required, with the CFV-39) is awkward, well, for me at least.

    -Brad
    Yes Brad
    It is akward , for me too , but I have tried that many times now , and I believe , I can get used to it .

    I noticed , that we have to accept compromises , but I see the big advantage in having finally a bigger sensor back for the V-SYSTEM .

    Jürgen

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    Re: Hasselblad RM-2 Viewfinder Modification (for 203FE)

    Quote Originally Posted by douglasf13 View Post
    Interesting, Marc. Is that what you use for portrait mode with the CFV? I would have that the angle would be strange, but I guess not.
    Well, I tried it after all the discussion about using the new 645 CFV in portrait orientation, and was surprised how well the PM45 worked ... someone else tried it also and found the same thing.

    It just might be worth a try at the very least.

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