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What do you saw off older Mamiya lenses to fit on Phase XF body? :)

faneuil

Member
I know you can mod older manual mamiya lenses to engage the XF.
Anybody know what I have to grind off?
(I don't have said lens in my hands yet-- but I am willing to take my dremel to it!)

Eric
 

faneuil

Member
Exactly -- for the 24mm I just picked up!


Not being brave enough to do this myself on my Mamiya 24mm it cost me £50 to get it done by a camera repairer in London. It's quite simple if you know what you are doing and not too costly if you don't.
 

0beone

Active member
Very interesting indeed!
A question: how do these lenses stack up with say up to 80 MP backs? does anyone here have images they would like to share with this lens type and XF combination.

Looking forward to your input.
Cheers
Frank
 

faneuil

Member
Will find out soon. The 24mm fisheye is supposed to be quite sharp.
I plan to test it with IQ180 and defish software -- I'd like to see how it does with interior photography (I can't cough up enough for the new 35mm LS quite yet.. I have the old 35mm which is.. ok..)

Eric



Very interesting indeed!
A question: how do these lenses stack up with say up to 80 MP backs? does anyone here have images they would like to share with this lens type and XF combination.

Looking forward to your input.
Cheers
Frank
 

0beone

Active member
Thanks Eric, Look forward to seeing the results. Bye the way the mod doesn't look to difficult - good luck with it.

Cheers
Frank
 

faneuil

Member
thanks all - the MF crowd is always so friendly (and cash strapped I assume :)

Gorgeous Mamiya 24mm C arrived yesterday!
I tried to remove the bayonet screws but they are SUPER tight and started to want to strip. so *full stop* !
sending it off to SK Grimes for the professional touch.

thanks again
eric

www.korenman.com
 

Transposure

New member
thanks all - the MF crowd is always so friendly (and cash strapped I assume :)

Gorgeous Mamiya 24mm C arrived yesterday!
I tried to remove the bayonet screws but they are SUPER tight and started to want to strip. so *full stop* !
sending it off to SK Grimes for the professional touch.

thanks again
eric

www.korenman.com

Eric,
It is funny that you mentioned SK Grimes. I never hear dog them until a week ago and inquired about a project. Great resource. Good luck.
Looking forward to the results.
Ken
 

0beone

Active member
thanks all - the MF crowd is always so friendly (and cash strapped I assume :)

Gorgeous Mamiya 24mm C arrived yesterday!
I tried to remove the bayonet screws but they are SUPER tight and started to want to strip. so *full stop* !
sending it off to SK Grimes for the professional touch.

thanks again
eric

www.korenman.com
A pity about that, will still be interesting to see the result when you get it back.

Cheers
Frank
 
M

mjr

Guest
Evening

These old Mamiya lenses cost nothing, any recommendations as to what to pick up and convert? Anything with some character for portraits etc? I feel like playing around with some alternatives on the XF.

Thanks in advance

Mat
 

ondebanks

Member
Evening

These old Mamiya lenses cost nothing, any recommendations as to what to pick up and convert? Anything with some character for portraits etc? I feel like playing around with some alternatives on the XF.

Thanks in advance

Mat
Here are some I've used, on both film and digital, and recommend:

The 80/1.9, as Graham said. A bit soft wide open (but worth it for the very thin DOF and low-light performance). Very good from f2.8 down.

The 24/4 ULD fisheye which you recently got - very very sharp. I use it a lot on my old square DCS645M back, and de-fish it to yield a "digital Biogon" equivalent (same FOV and aspect ratio as the Hasselblad SWC 38mm Biogon on 6x6 film). Great for interiors.

The 200/2.8 APO is awesome. I haven't tried the 300/2.8 or 500/4.5 APOs, but they are said to be the same.

Most of the other old M645 C/S/N/A lenses have equivalents in the AF lineup, but that doesn't necessarily mean that they are inferior; in several cases they were optically the same. The 120/4 A macro is a case in point - a really sharp and hugely versatile lens: designed for 1:1 macro, also great for portraits as you can get close without extension tubes, and even pinpoint across the field at infinity (though it vignettes more at infinity than a non-macro lens).

In addition to the ones I've described, I have or had the 35/3.5 N, 45/2.8 C and 45/2.8 S, 55/2.8 N, 70/2.8 C LS, 110/2.8 N, 150/3.5 C, 150/2.8 A, and 210/4 N in primes; 105-210/4.5 ULD C and 55-110/4.5 AF in zooms; and a couple of 2x N teleconverters.

The 24/4, 45/2.8 S, 120/4, and 200/2.8 are the only M645 lenses I've used which meet my expectations, wide open.

I will shoot the others wide open if I have to (astrophotography tends to demand this) but 1 stop down is where they begin to impress. The best ones in this category are the 55/2.8 N and 55-110/4.5 AF.

The old 45/2.8 C is disappointing off-axis (hence its relatively early redesign to the S), and the only one of which I will say "don't bother".

The 150/2.8 A is disappointing for a different reason: it's a very good lens but nevertheless it's the only one of the 1990s A series to be softish wide open. As the 3rd iteration of the 150mm series, after the 150/4 and 150/3.5, I expected better.

There's such a large M645 ecosystem that I've only experienced about half of it. Ones I haven't tried include the 50/4 shift, 145/4 soft focus, 75-150 C zoom, 300/2.8, 300/5.6, 500/4.5 and 500/5.6 telephotos, and 500/8 mirror telephoto.

And don't get me started on adapted lenses from other MF systems...that's a whole other lengthy post I could write!

Ray
 

MILESF

Member
The 24/4 ULD fisheye which you recently got - very very sharp. I use it a lot on my old square DCS645M back, and de-fish it to yield a "digital Biogon" equivalent (same FOV and aspect ratio as the Hasselblad SWC 38mm Biogon on 6x6 film). Great for interiors.
Ray, May I ask what defishing software you use ? I have an XF converted 24mm lens and would like to give this a try. Many thanks.
 

ondebanks

Member
Miles,

I use Hugin software. Its main purpose is stitching panoramas (where it excels), but it can also apply geometric and photometric corrections/reprojections to single frames.

When you load an image from the 24mm, choose "Full frame fisheye" as the lens type, 24mm as the focal length, leave the HFOV box empty (it will update itself automatically), and (this is the important bit!) enter a Focal Length Multiplier (aka crop factor) which depends on the ratio of your sensor's diagonal to the diagonal of full-frame 35mm.

I had to work that last bit out by a process of trial and error. I initially assumed the Focal Length Multiplier would be 0.74, from sqrt((36.7^2)+(36.7^2)) / sqrt((41.5^2)+(56^2)); i.e. the crop of the image sensor diagonal relative to the frame size on which this lens would be a 180 degree "full-frame fisheye", thus relative to the 645 diagonal...but that gave some obvious residual curvature in the previewer.

So in fact, Hugin anchors the Focal Length Multiplier for all images and sensors relative to 35mm full frame diagonal. Therefore the number I enter for my 36.7mm square back is 0.83, from sqrt((24^2)+(36^2)) / sqrt((36.7^2)+(36.7^2)).

Next, move to the "Stitcher" tab in Hugin, choose your desired projection (e.g. Rectilinear, Panini, ...), and click the 3 buttons below it in order: "Calculate field of view", "Calculate optimal size", and "Fit crop to images". You'll notice that it increases the image size, in order to cleverly preserve all of the central resolution as it reprojects and expands the outer parts of the image. Choose your desired output format from the drop-menu in the middle (TIFF, JPEG or PNG). You can ignore all the exposure/fusion/HDR stuff here, as you are only doing a single frame geometric correction.

Next, click the GL icon in the top menu bar, which opens an interactive preview window. Make any further changes you desire (e.g. remove keystoning in the "Move/Drag" tab); click the same 3 buttons on the Stitcher tab again to tidy up after such changes; and when you're happy click the "Stitch!" button in the bottom right corner. It will ask you to save the project metadata (.pto file) and then to name the output image before it computes it.

Here's an example, before and after:




Ray
 

MILESF

Member
I would just like to say a public thanks to Ray (Ondebanks) for his advice about defishing fisheye lenses. There have been some depressing threads on this forum recently. Ray reminds me that Getdpi is a and hopefully will continue to be a special place where people ask for advice and others give generously of their knwoledge and expertise. My decisions around a technical camera and lenses were largely informed by the experience and knowledge of people here. I have not regretted my choices for a moment.

Getdpi is a very special resource and I do hope that the advice and generosity of people like Ray will encourage others in the same directions; that newcomers are still welcome even when our questions are hesitant and perhaps poorly thought through; that debate is still lively but polite and that people continue to share knowldge and experience here.
 
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ondebanks

Member
Miles, thank you for your very kind feedback. :thumbup:

I have to say that I've always been motivated to give helpful information on getDPI and elsewhere for the same reason you cited - a community of like minds, sharing their expertise and experience, and supporting each other's learning. Down the years I've been the beneficiary of other people's expertise, so I like to "give back" in kind when I can.

Cheers,
Ray
 

0beone

Active member
Well, just for the fun of it I bought a near mint 45 f2.8s Mamiya Sekor "C" lens, cost me $134 incl freight.

The mod was easy enough and I did it with Dremel and the very thin "part-off" disks. Firstly making a vertical cut at each extremity
then from the inside of the plate slowly worked around the part that had to come off. Careful filing to finish then matt black paint.

Result: Outstanding... Fits nicely on the XF (remember you have to go to the Capture menu and go down till you get to manual lens then turn it on)

Will do a few test shots tomorrow and let you know how it goes quality-wise.

Cheers
Frank
 

0beone

Active member
Well, as a follow up I can say that this lens seems to be pretty good. The image quality corner to corner is excellent and I am just so happy with how it went. Mind you I am using this with a Credo-40 so it is a little cropped.
Is it as good as the current series of lenses? not a chance, but for the poor cash strapped who enter Dante's inferno it's not that bad either...

Currently on the look-out for a couple more, and at the price I think it's pretty good value!

Cheers
Frank
 
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