Ad
Ad
Ad
Pages: [1]   Bottom of Page
Print
Author Topic: View camera question  (Read 14590 times)
Randall
Newbie
*
Offline Offline

Posts: 25


« on: April 16, 2006, 05:57:07 PM »
ReplyReply

If this is an old idea, please forgive me.  

Have any view camera/digiback users experimented with  removing the front lens board and the bellows, and mounting a helicoid 24mm of 35 mm lens in a reversed recessed lens board (likely 15mm) in the front of the rear standard (leaving the front standard empty of removed?

With a sliding back in place (Kapture group or similar) it would seem that you retain "shift" and answer the parrallelism problem for these short lenses, and eliminate the need for an additional Alpa/Cambo type system.

Randall
Logged
Lester
Full Member
***
Offline Offline

Posts: 146


« Reply #1 on: April 16, 2006, 07:19:07 PM »
ReplyReply

Have any view camera/digiback users experimented with  removing the front lens board and the bellows, and mounting a helicoid 24mm of 35 mm lens in a reversed recessed lens board (likely 15mm) in the front of the rear standard (leaving the front standard empty of removed?

It sound like a hell of a idea, I got a Arca-Swiss and I have a hell of a time with the 24mm lens getting it in focus with the Kapture sliding back.

If someone done it and it works, I would like to know about it.
Logged

I am a old fart, over 60
free1000
Sr. Member
****
Offline Offline

Posts: 401


WWW
« Reply #2 on: April 17, 2006, 02:23:12 AM »
ReplyReply

Quote
If this is an old idea, please forgive me. 

Have any view camera/digiback users experimented with  removing the front lens board and the bellows, and mounting a helicoid 24mm of 35 mm lens in a reversed recessed lens board (likely 15mm) in the front of the rear standard (leaving the front standard empty of removed?

With a sliding back in place (Kapture group or similar) it would seem that you retain "shift" and answer the parrallelism problem for these short lenses, and eliminate the need for an additional Alpa/Cambo type system.

Randall
[a href=\"index.php?act=findpost&pid=62744\"][{POST_SNAPBACK}][/a]

Interesting.... I guess that you mean, mounting a helicoid 24mm  "or" 35mm lens such as a Schneider 35XL.

This might just work, but the question is how deep is the Kapture group focal plane? The 35XL only has a flange-focal length of around 35mm. If your rear standad is 15mm deep and the Kapture group depth is 20mm then you certainly need the recessed lens board, things are getting tight though.

However... your sliding back adapter will only allow horizontal movements. There will be no rise or fall possible with such a camera and this is usually the one essential movement for architectural use.

You also have to take into account the fact that with view cameras it is already possible to mount and use a 35mm lens. So this scheme does not add advantages for a 35mm.

However this is very interesting in the 24mm case, because that lens allows for no practical movements. So rise is not possible. In this case, it might save the cost of a second camera. I might consider this as the adaptation you suggest would be easy to make with a Cambo Ultima 54 which has very simple mounting plates.

With the forthcoming Rodenstock Linos 28HR, rise/fall of about 6mm *is* possible and this would probably be a useful amount of shift. So not good for this lens.

For the moment (I am ordering my MFDB this week) I have decided to use my Cambo Ultima, because I calculate that with a stitched image, I am getting a greater angle of view than with the 24mm lens without needing to carry a second camera. (15mm vs 18mm equivalent in 35mm camera terms)

I understand that focussing the 35 will be problematic on my Ultima, but I think that the tradeoff may be adequate given the resulting flexibility, ease of switching to 6x9 and 5x4 film and so on.

If I can work with this system, then I don't need a lens wider than 35mm. I will just stitch images for the shots needing a wide angle result.

I think that the 28mm and 24mm lenses are quite exotic and their lack of image circle and movements limits their flexibility.

I am likely to use the 35 from Rodenstock as it has a larger image circle than the Schneider. It also has a slightly longer flange to focal length quoted in the tech specs.  I calculate that with this lens and using stitching I could achieve the angle of view of the 24mm Schneider, and leave enough image circle for some shift movement into the bargain.
Logged

@foliobook
Foliobook professional photography folio for iPad
www.foliobook.mobi
free1000
Sr. Member
****
Offline Offline

Posts: 401


WWW
« Reply #3 on: April 17, 2006, 02:43:51 AM »
ReplyReply

Another snag with the idea (sorry)...

I just tried to make a diagram of the 24mm lens idea... then realised almost instantly that the helical mount would bury the 24xl deep into the recessed lens board. Then I wonder how accessible it would be for focussing. This might work if you could attach a dog leg to the mount (you'd need that for the shutter controls and release as well possibly).

Using an electronic shutter like the schneider might help decrease the size... but its all looking rather tricky.
Logged

@foliobook
Foliobook professional photography folio for iPad
www.foliobook.mobi
dazzajl
Jr. Member
**
Offline Offline

Posts: 71


« Reply #4 on: April 17, 2006, 05:16:04 AM »
ReplyReply

For what it's worth I use a 28mm lens on my Cambo ultima without any real problems. It doesn't make for the most fluid system in the world but it's perfectly usable and allows enought movement to very worth the effort.
Logged
free1000
Sr. Member
****
Offline Offline

Posts: 401


WWW
« Reply #5 on: April 17, 2006, 09:40:18 AM »
ReplyReply

Yes, but I assume that you are talking about the Schneider 28mm lens? This is a retrofocus design, same optics as those on the SLR mountable 28 shift lenses.

I bought one and returned it because I found its levels of distortion (moustache distortion, not simple barrel, hence difficult to correct once shifted)  unacceptable for my work.

Your milage may vary.
Logged

@foliobook
Foliobook professional photography folio for iPad
www.foliobook.mobi
Randall
Newbie
*
Offline Offline

Posts: 25


« Reply #6 on: April 17, 2006, 10:43:38 AM »
ReplyReply

Quote
Another snag with the idea (sorry)...

I just tried to make a diagram of the 24mm lens idea... then realised almost instantly that the helical mount would bury the 24xl deep into the recessed lens board. Then I wonder how accessible it would be for focussing. This might work if you could attach a dog leg to the mount (you'd need that for the shutter controls and release as well possibly).

Using an electronic shutter like the schneider might help decrease the size... but its all looking rather tricky.
[a href=\"index.php?act=findpost&pid=62775\"][{POST_SNAPBACK}][/a]


The rear standard on an Arca Metric 6X9 is a bit less than 1cm.  The Kapture Group back from the back of the lensboard to the sensor looks to be about 1.5 cm.  The Flange Focal distance on the Digitar 24 XL is 26.4 (or 24.2).
Logged
Randall
Newbie
*
Offline Offline

Posts: 25


« Reply #7 on: April 17, 2006, 10:49:22 AM »
ReplyReply

Quote
Interesting.... I guess that you mean, mounting a helicoid 24mm  "or" 35mm lens such as a Schneider 35XL.

Apologies for the typo.  Yes that is what I meant.
Logged
Randall
Newbie
*
Offline Offline

Posts: 25


« Reply #8 on: April 17, 2006, 01:16:22 PM »
ReplyReply

Quote
If this is an old idea, please forgive me. 

Have any view camera/digiback users experimented with  removing the front lens board and the bellows, and mounting a helicoid 24mm of 35 mm lens in a reversed recessed lens board (likely 15mm) in the front of the rear standard (leaving the front standard empty of removed?

With a sliding back in place (Kapture group or similar) it would seem that you retain "shift" and answer the parrallelism problem for these short lenses, and eliminate the need for an additional Alpa/Cambo type system.

Randall
[a href=\"index.php?act=findpost&pid=62744\"][{POST_SNAPBACK}][/a]

One other note of interest,

Kapture Group will be introducing a quad stitch back in the next week.  That means XY movements.
Logged
free1000
Sr. Member
****
Offline Offline

Posts: 401


WWW
« Reply #9 on: April 17, 2006, 03:36:42 PM »
ReplyReply

Hmm, maybe you could make this work... I'm not trying to dismiss the idea out of hand. I would like it to work.
 
Specifically I was hoping that I could use the KG sliding adapter with my Cambo and a 35mm lens. The Cambo adapter is a little thinner I think, but it is limited in possible stitching directions.
 
I just had these figures from the Kapture group for the existing stitching adapter, these are described as "approximate" by KG.

The sliding adapter is 13.5mm thick
The chip film plane is an additional 3.95mm back

So about 17.5mm  plus the depth of the standard say about 1cm making 27.5, so with a recessed lens board it would work. With my Ultima 45 you can get a lensboard recessed to 25mm... more than is necessary for either the 24XL or the 24XL...

This is interesting... presumably you could use the quad stitching adapter to achieve rear rise and fall in this case. According to the Kapture Group the quad adapter will be thicker. But I guess this would not be a problem.
 
What helicoidal mounts did you have in mind?
Logged

@foliobook
Foliobook professional photography folio for iPad
www.foliobook.mobi
Randall
Newbie
*
Offline Offline

Posts: 25


« Reply #10 on: April 17, 2006, 08:32:44 PM »
ReplyReply

Quote
The sliding adapter is 13.5mm thick
The chip film plane is an additional 3.95mm back

So about 17.5mm  plus the depth of the standard say about 1cm making 27.5, so with a recessed lens board it would work. With my Ultima 45 you can get a lensboard recessed to 25mm... more than is necessary for either the 24XL or the 24XL...

And you could reduce the 1 cm you had figured for the standard by about 2 more millimeters for the lensboard which has already been accounted for in the flange measurement.

I had not considered a specific helicoid mount yet.  Actually, I was hoping someone might have already done some experimenting.
Logged
free1000
Sr. Member
****
Offline Offline

Posts: 401


WWW
« Reply #11 on: April 18, 2006, 02:02:45 AM »
ReplyReply

On the helicoidal mounts, it seems quite cost effective to have lenses mounted by Silvestri.

They charge 300 per lens. That includes the helicoidal mount and a Silvestri bayonet fitting. They also quoted for fitting a linhof lens board with the female bayonet fitting for about 100 labour + any components needed.
 
This also has the possible advantage of compatibility with the Silvestri system.

Further thoughts :

With the Schneider 24mm lens the distance from the rear of the lens to the focussing plane is only 12mm or 10mm! (depends on shutter, but Schneider don't quote this for the bulkier copal shutter only for electronic shutters).  As this distance is less than the focus depth of the Kapture sliding back, I don't think that this lens would be viable with a sliding back as the lens end would need to nestle inside the sliding adapter. But it might be OK if you focussed on a GG and then replaced with a mounted back with no sliding adapter. Or possibly you could use infinity focussing a la the Cambo Wide DS once you had your back adapter shimmed correctly.

With the Schneider 35 or Rodenstock 35, the distance is either 24mm (Schneider) or 18mm (Rodenstock) hence these lenses could be used with a standard view camera set up... with the Schneider at a slight advantage in flexibility but with a smaller image circle. The Rodenstock would barely work with the KG adapter given the adapters 17.95mm focal depth.  

Note that with the KG adapter and the 35mm lens you could get a stitched image 48x72mm (Portrait stitch). This gives a similar angle of view to an 18mm lens (35mm equivalent) according to my calculations based on Andre Oldani's lens calculation spreadsheet (see www.alpa.ch). A 24mm lens on a 36x48mm sensor gives a similar angle of view to a 17mm lens (35mm equivalent).  Therefore the 24mm doesn't buy much advantage if you are prepared to stitch images with the 35mm lens. The only downside is the extra post work and the longer camera to subject distance involved with the stitching option. Having the 24mm might provide a "get out of jail free card" for some tight spots though, I'd find access to one pretty essential for many interiors scenarios.

Gradually I am being pushed towards the Cambo Wide solution... I think it's one of the few cameras today that allows both mounting the 24XL and stitching with a 35mm lens at a price affordable by a working professional rather than a corporate lawyer.  

View cameras cannot mount the 24XL at all.
Cambo Wide DS allows X/Y stitching, in both portrait and landscape orientation
Silvestri Bicam can mount both but cannot stitch (yet).
Alpa SWx can mount both, and I don't know about stitching.
Alpa XY will do anything to space science precision... at prices suitable for ESA and NASA?  
There are a few smaller, custom manufacturers... but what about support?
« Last Edit: April 18, 2006, 02:10:46 AM by free1000 » Logged

@foliobook
Foliobook professional photography folio for iPad
www.foliobook.mobi
Randall
Newbie
*
Offline Offline

Posts: 25


« Reply #12 on: April 18, 2006, 10:56:38 AM »
ReplyReply

A couple more thoughts.  

Most of the KG sliding back directly behind the lens board is hollow, and without interference from the sliding portion of the back.  The rear element of the lens could use this space, just as it would the interior of the camera.  

I wonder how much the Silvestri mount changes the distance of lens board to sensor at infinity focus.  Of course all of the different mounts, (Hasselblad V, H, Contax etc) use different sensor spacing.
Logged
Jae_Moon
Full Member
***
Offline Offline

Posts: 133


WWW
« Reply #13 on: April 18, 2006, 03:31:11 PM »
ReplyReply

Randall:

I am a newbie to LF & DB, and I have a question you may able to answer. I am in process of getting ARCA F69 with a DB but I haven't decided if I want to have a stitching back, such as one from KG.

Q, how a stictching back mounts to the back standard? Does it requires an adapter?
Logged
dazzajl
Jr. Member
**
Offline Offline

Posts: 71


« Reply #14 on: April 18, 2006, 04:01:04 PM »
ReplyReply

Quote
Yes, but I assume that you are talking about the Schneider 28mm lens? This is a retrofocus design, same optics as those on the SLR mountable 28 shift lenses.

I bought one and returned it because I found its levels of distortion (moustache distortion, not simple barrel, hence difficult to correct once shifted)  unacceptable for my work.

Your milage may vary.
[a href=\"index.php?act=findpost&pid=62791\"][{POST_SNAPBACK}][/a]

Schneider Digitar 28mm, there may be others, I wouldn't know. I don't tend to go much deeper into what's available than what I need to know. It goes on the front of the camera and I shoot, works for me.  

If it is the same, I'm surprised you found excessive distortion. I've found it to be very true, although there is no getting away from the fact that it's very wide on a 645(ish) sensor. Used in small spaces the perspective can be unatractive without some normal wide angle distortion, to set the scene.

On the subject of stitching backs, if your just specing out a new system I would a have a good thnk about what it's really going to do for you.  You have the capability to move the back around on a LF camera anyway, so unless you are going to get some real benefit from making that happen a little quicker, the money may be better spent elsewhere.
Logged
Randall
Newbie
*
Offline Offline

Posts: 25


« Reply #15 on: April 18, 2006, 05:00:19 PM »
ReplyReply

Quote
Randall:

I am a newbie to LF & DB, and I have a question you may able to answer. I am in process of getting ARCA F69 with a DB but I haven't decided if I want to have a stitching back, such as one from KG.

Q, how a stictching back mounts to the back standard? Does it requires an adapter?
[a href=\"index.php?act=findpost&pid=62984\"][{POST_SNAPBACK}][/a]

Hello Jae,

I am shooting with a Arca 6x9 F metric.  The camera side of the KG stiching adaptor is a lensboard, so you simply attached it into the lens board receptor on the rear standard.  I would suggest the stitching back.  Mine stays on the camera at all times with a RMfx viewer, the P25, a lens with cable release, and the sync cable.  Just pull it out of the bag and get right to work.  Stitching becomes so easy, that you simply do it more, and the results are 4x5 quality.

Best of luck,

Randall
Logged
Jae_Moon
Full Member
***
Offline Offline

Posts: 133


WWW
« Reply #16 on: April 19, 2006, 09:21:09 AM »
ReplyReply

Quote
Hello Jae,

I am shooting with a Arca 6x9 F metric.  The camera side of the KG stiching adaptor is a lensboard, so you simply attached it into the lens board receptor on the rear standard.  I would suggest the stitching back.  Mine stays on the camera at all times with a RMfx viewer, the P25, a lens with cable release, and the sync cable.  Just pull it out of the bag and get right to work.  Stitching becomes so easy, that you simply do it more, and the results are 4x5 quality.

Best of luck,

Randall
[a href=\"index.php?act=findpost&pid=62998\"][{POST_SNAPBACK}][/a]

Thank you, Randall, one more question.

What is the shortest Schneider lens one can use with KG Stitching back in 69F? 35mm?

Jae M
Logged
Randall
Newbie
*
Offline Offline

Posts: 25


« Reply #17 on: April 19, 2006, 11:12:47 AM »
ReplyReply

Quote
Thank you, Randall, one more question.

What is the shortest Schneider lens one can use with KG Stitching back in 69F? 35mm?

Jae M
[a href=\"index.php?act=findpost&pid=63067\"][{POST_SNAPBACK}][/a]

The 28 L should work fine, although I have never tried it.  The flange focal distance is 69.9 on that lens, so longer than the 47.
Logged
Pages: [1]   Top of Page
Print
Jump to:  

Ad
Ad
Ad