sliding back suggestions

[JoeKitchen]

my first captures are typically sharp, frequently requiring very little or no focus adjustment.

Is this to say that the back tends to fall out of plane after a few exposures?

[LiamStrain]

if you have an RM3D then you can buy a special adaptor (special order around 300$) for RM3D lenses on arca 110.

but there is one limitation... it's a flat adaptor !

to mount the lenses on your M2, you need to remove both rings from the lens and to screw the lense onto the adaptor lensboard.


you have a second option, is to use the  RM3D as a front standard, and then you need a short support for the back (misura style).

The flat adapter sounds like the way to go then, since you get the full range of movements allowed by lens and M2 no? If you use the RM3D as the front standard, and just the M2 back, you would be limited just to a small range of shifts, since the back would be right up against the body? Or am I missing something.

[archivue]

The flat adapter sounds like the way to go then, since you get the full range of movements allowed by lens and M2 no? If you use the RM3D as the front standard, and just the M2 back, you would be limited just to a small range of shifts, since the back would be right up against the body? Or am I missing something.

it depends... in the studio, i will go for the flat adapter and the M2... but on location, it's quite cool to be able to mount a bellow and a rail for a longer lens...

But it can be usefull to be able to use the RM3D and the focusing ring as front standard for "Helicon Focus' stuff !

[archivue]

[Kumar]

I've used Widepan, Mergin-X and Phase One stitching backs and a Sinar sliding back on a Sinar F2, P and X. The Sinar back is the most rigid and problem free. It mounts directly onto the rear carrier, so the tilt and swing axes are correctly positioned. I've found that stitching using the geared shift and rise/fall movements on the Sinar P and X is far better than using a stitching back.

I also have a fixed Graflok adapter that I used on a Cambo WideDS. With the Cambo, focusing and attaching/re-attaching the back was problematic, and the potential for accidents greatly increased.

I have a question arising from this.

Why don't MFDB's have dark slides?

They are designed to fit in place of film backs - which have dark slides. I know Rainier Viertlbock got his Gottschalt camera modified to have one, so it is possible. What  are the technical reasons behind this? If there was a dark slide, there would be no need for a sliding back, at least for me.

Kumar

[CBarrett]

Why don't MFDB's have dark slides?

They are designed to fit in place of film backs - which have dark slides. I know Rainier Viertlbock got his Gottschalt camera modified to have one, so it is possible. What  are the technical reasons behind this? If there was a dark slide, there would be no need for a sliding back.

Kumar

Hmm... my P65+ has a cover plate, which provides more protection than a dark slide would and takes about the same time / effort to use.  And actually, when I move from shot to shot I take the digi back off the sliding back and put it in the camera case.  I just don't feel comfortable throwing the camera over my shoulder with a $40k back hanging off of it.

RM3D First Impression:  REALLY DAMN NICE!  All movements are silky smooth and the tilt is ingenious.  I focused the 35mm using the groundglass, took it off and put the digi back on and was tack sharp.  Actually, I was slightly off when wide open but at f/11 it was all good.  Focusing was really easy with the big ring.

My Kapture Group Slider does work fine on the RM3D, depth must be close enough to the Rotaslide that focus seems fine.  The camera didn't come with a Rotaslide, so can't test that.  I'm taking the RM3D out on an interiors shoot tomorrow and look forward to spending the day with it!

-CB

[asf]

I focused the 35mm using the groundglass, took it off and put the digi back on and was tack sharp.  Actually, I was slightly off when wide open but at f/11 it was all good.  Focusing was really easy with the big ring.

Can you explain this a bit further - you were off or it was off? f11 on a 35 will tend to make up for slight focus problems.
Also which 35 is it? The rodenstock HR is meant to be sharp to the edges from f4 ...

[Kumar]

Hmm... my P65+ has a cover plate, which provides more protection than a dark slide would and takes about the same time / effort to use.  And actually, when I move from shot to shot I take the digi back off the sliding back and put it in the camera case.  I just don't feel comfortable throwing the camera over my shoulder with a $40k back hanging off of it.

-CB

All digital backs come with cover plates. The greatest risk of putting a scratch on the sensor is when mounting it on the camera. A slight inadvertent turn of the hand, and ...
The dark slide would not only prevent this from happening, but would also greatly reduce the amount of dust on the sensor.

I think most everyone does take care to remove the back from the camera while moving from shot to shot. The dark slide would add protection while mounting the back. And of course, the cover plate, being a thicker and rigid metal plate would be additional protection.

So does anyone know why MFDB's don't have dark slides?

Kumar

[yaya]

So does anyone know why MFDB's don't have dark slides?
Kumar

Film backs do not need an IR filter, so between the film plane and the camera's back plate plane there is space for a dark slide.

Digital sensors require an IR filter which needs to sit in a certain distance from the sensor (for optical reasons) and in most cases there is no room for an additional layer between the filter and the camera's back plate plane.

Yair

[Kumar]

Film backs do not need an IR filter, so between the film plane and the camera's back plate plane there is space for a dark slide.

Digital sensors require an IR filter which needs to sit in a certain distance from the sensor (for optical reasons) and in most cases there is no room for an additional layer between the filter and the camera's back plate plane.

Yair

Yes, of course. Forgot about that! I'll see if I can figure out something for my Sinars.

Kumar

[Dick Roadnight]

"Dark slide" for digibacks

Yes, of course. Forgot about that! I'll see if I can figure out something for my Sinars.

Kumar

Is the sensor not protected when slid out of the way for focussing?

With wide angles, there is not any spare distance for a sliding cover, but with a Sinar you get the slot where you inserted the ground glass and then the film holder...

Given sufficient room, (depending on bellows and lens) it would be simple to incorporate a slide into the adaptor or the sliding back.

You could leave the back attached to the lensboard and adaptor, and use a standard frame holder (which has two slots, one for the bellows and one for the lensboard) an use a standard blank (no hole) lensboard as a slide.

... or you could make a non-standard triple slot lens-board/frame holder and use the middle slot for a protective slide.

This would all be less bulky with a Sinar P3.

[Kumar]

"Dark slide" for digibacks

Is the sensor not protected when slid out of the way for focussing?

With wide angles, there is not any spare distance for a sliding cover, but with a Sinar you get the slot where you inserted the ground glass and then the film holder...

Given sufficient room, (depending on bellows and lens) it would be simple to incorporate a slide into the adaptor or the sliding back.

You could leave the back attached to the lensboard and adaptor, and use a standard frame holder (which has two slots, one for the bellows and one for the lensboard) an use a standard blank (no hole) lensboard as a slide.

... or you could make a non-standard triple slot lens-board/frame holder and use the middle slot for a protective slide.

This would all be less bulky with a Sinar P3.

Yes, the sensor is protected when slid out of the way for focusing on a sliding back. What I'm trying to figure out is a way to protect the sensor when attaching/removing the digi back on a view camera, much like a dark slide in a conventional roll-film holder.

Kumar

[Dick Roadnight]

I asked Kapture group:

"I am interested in the three-position adaptor for the 60Mpx Hasselblad digiback and the Sinar P3... what image and pixel sizes would this produce?  53.7 * 90mm & 134 Mpx? That would be 24 * 41 inches @ 360 original camera pixels per print inch!"

They said:

We currently offer a 2 or 3 position stitch adapter that have the following coverage area.

2 x Landscape  83.40 mm x 40.4 mm
3 x Portrait 75.8 mm x 53.9 mm

...and they are looking into making a sliding back for the 60Mpx sensors.


I replied:

Can you give me some indication when the sliding back for the 60Mpx sensors will be available, and will it be available for the P3 giving a 53.7 * 90mm image or what?

Can you supply "universal" sliding backs without detents?

Would you consider a 9*9cm ground glass for use with the rear rise/fall on a Sinar P3 with the triple stitch back for hex-stich?

I am thinking of mortising one for remote use on a 10m tripod: I am an agricultural electronic engineer who once contemplated a career in robotics.

[Hank Keeton]

I use one from Widepan in China, $350 on eBay. Sinar-Hassy-V. Simple. Works smoothly. I can 3-shot stich in portrait-mode for pretty intense files. Also use rear rise/fall/shift to augment as inspired.

[Rod.Klukas]

Honestly, I'm not quite sure how I would go about that.  I can place a dial indicator along the base and look for a variance as I slide the back over.  This would tell you if one slider has more slop than the other.  But as far as comparing focal planes... I'm not sure what I'd do... maybe place a block across the standard and measure down to the surface of the UV filter and then where do you measure on the groundglass?  Where exactly does the focal plane lie?  Somewhere between the screen and the fresnel?  Even if it was the inner face of the fresnel, which I believe it is not, the measuring device would have to move and I wouldn't expect high accuracy, at least not with the tools that I've got, which are mainly used in restoring old motorcycles  : )

I could do a visual test, though and just see which one actually gives me a sharp image after focusing with a loupe, which is really what we're all after anyway, no?  Then again, the test is subject to the deficiencies of 40 year old eyes.

-CB

Chris,
You are correct about difficulty checking for depth variation between gg position
and sensor plane.  The actual plane resides below physical surface of sensor.
Because of this the physical distances will not coincide.  Arca actually takes this into consideration when mounting
RM3d lenses.  They test to actual backs with each lens.  What this also points out is that there may be a variance
with a traditional view camera with any particular digital back, so testing may be required with a new back, and or camera.
Rod