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Large-format effect with a FF digital camera
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PostPosted: Wed Feb 07, 2018 1:44 am    Post subject: Large-format effect with a FF digital camera Reply with quote

Have you looked through this article, with its embedded shots and the video? The idea itself of the construction seems smart and the result does pair with those old looking deep-DOF images. The IQ made me think of a combined effect of an f1.2 and tele lens, but fairly sharper.

What do you think, from technical and esthetic points of view, of this re-filming the matte screen?


PostPosted: Wed Feb 07, 2018 3:50 am    Post subject: Reply with quote

Well, kudos to the kid for stickwithitness and originality. The images have a remarkable daguerreotype quality to them. I wonder how much of the effect he's achieving is due to the good ole Scheimpflug rule, though -- assuming, of course, he's using all the movements available with the large format portion of his rig. Naw, Scheimpflug is used mostly for perspective and DOF control. Looking at his stills he doesn't appear to be overly concerned with either. So then I wonder about that old Industar lens. Maybe it's providing "the look."


PostPosted: Wed Feb 07, 2018 5:14 am    Post subject: Reply with quote

I have seen this sort of idea done before - basically shooting the groundglass (a specialized one) of an LF camera. The ones I have seen are done from behind the specialized groundglass, that is, in line with the projected image.

May want to try this actually. I have several 4x5 cameras and similar for such an experiment. The replacement screen is critical, and that bit requires experiments, as he said, a very matte finish, and if in-line, something like a fresnel that reduces light falloff off axis. Also extremely clean.

His rig is off-axis, with the digital camera underneath, and thats why he needs the PC adapter and that 15mm FF lens, which gives room on its image circle for movements. So he doesn't have to shoot through, just shoot at. Clever.

But not everyone has the $ for a 15mm FF lens for such a tinkerers project. So there must be another way.

If your goal is extreme shallow dof the longer the FL of your LF lens the better, and thus a bigger screen/larger camera, but I have a secret weapon, a 16.5cm Biotessar f/2.8, which is something that should give DOF effects of an f/4.5 300mm Tessar type which he seems to be using, but on 4x5 instead of 8x10.

Good idea and worth an experiment.


PostPosted: Wed Feb 07, 2018 6:57 am    Post subject: Reply with quote

I do basically the same since 2016, but on a larger inter image format and still in prototype stage.
I work up to now with a epidiascope lens 480mm f/3.8 at ideally crop 0.1:

Portrait by Markus, auf Flickr

Bearded-Man by Markus, auf Flickr

After a bigger renovation in our flat, I can now start working on the real deal, to get my camera moveable (without a car).


PostPosted: Wed Feb 07, 2018 6:58 am    Post subject: Reply with quote

Hey, if extremely shallow depth of field is the desired effect, then why not just use a very fast lens and be done with it.

For example, the Canon FD 85mm f/1.2 L or Aspherical. I have a copy of the Aspherical. Here's a shot I made with my 85 Aspherical set wide open. I was using my Canon F-1 and shooting Kodak Elite Chrome 100 slide film. The point of focus was the lettering on the camera's lens.



Same camera and lens. Lens wide open. Fuji Superia 400 film.


This was shot with my 10.1mp Canon DSLR. I used an adapter with no glass, hence macro only. Same as above, 85 wide open.


The point of focus in the above image:


The edge of our storage barn. A study in depth of field/bokeh. Same lens, wide open, NEX 7 at ISO 100.


Last edited by cooltouch on Fri Feb 09, 2018 3:13 pm; edited 4 times in total


PostPosted: Wed Feb 07, 2018 7:00 am    Post subject: Reply with quote

On my ultra large format camera I have something like 48mm f/0.38 relative to 24x36mm imaging - at the moment.
So this puts my Mitakon 50mm f:0.95 to shame in terms of DOF.


PostPosted: Wed Feb 07, 2018 7:03 am    Post subject: Reply with quote

luisalegria wrote:
But not everyone has the $ for a 15mm FF lens for such a tinkerers project. So there must be another way.
...


I use in my way the Russian 35mm f/2.8 shift lens. But its quality is not that good when the full shift is needed.
Furthermore it is quite slow.


PostPosted: Wed Feb 07, 2018 7:09 am    Post subject: Reply with quote

Its not a weird lens, its just very shallow dof due to a long focal length.
The kicker though is that this shallow dof is achieved on a "normal" field of view, an 8x10 projected image, for which 300mm is "normal".

Thats part of the magic of large format. An f/4.5 Tessar like he's got (that what it probably is), on large format, has narrower dof for a similarly framed subject than a 50mm f/1 on 35mm/FF.


PostPosted: Wed Feb 07, 2018 7:30 am    Post subject: Reply with quote

Good luck Marcus.
You have great samples.

Show us your version when you can.


PostPosted: Wed Feb 07, 2018 12:59 pm    Post subject: Reply with quote

Quite interesting, wonder if I should build something the like myself, always a nice challenge for an engineer Wink


PostPosted: Wed Feb 07, 2018 1:38 pm    Post subject: Reply with quote

Use process lens inside nested boxes. Project a nice big like 24x36" ground glass...


PostPosted: Wed Feb 07, 2018 2:20 pm    Post subject: Reply with quote

I have a 300mm f/5.6 Tessar that I bought at an astronomy swap meet years ago. Never done anything with it. The seller told me it was from a paint comparitor. Okay. More recently I've found plans and examples of "copyscopes" made from this optic. Apparently it makes a good wide-field telescope.

I snagged this image of the Tessar off the 'net:


If you google "copyscope" you'll get lots of hits. After you do, be sure to click on the option that searchs for "copyscope" only and not "copyscape" also.

Here's one site that I've known about for years. When I finally get around to building mine, I'm going to use it as a resource:

http://www.dma1.org/~wagner/copyscop.htm

Here's a really nice copyscope somebody built using the same Tessar I have:

https://www.cloudynights.com/articles/cat/articles/carl-zeiss-300mm-f56-s-tessar-rft-r3044


Last edited by cooltouch on Wed Feb 07, 2018 2:29 pm; edited 1 time in total


PostPosted: Wed Feb 07, 2018 2:21 pm    Post subject: Reply with quote

kds315* wrote:
Quite interesting, wonder if I should build something the like myself, always a nice challenge for an engineer Wink


I played with something like this a while ago and it's not difficult to do the large format part. I used my 1896 5x7 Lancaster camera with a 4.5/210 Ross Xpress (Tessar type).

All I did was frame the subject as per usual on the ground glass, hold the shutter of the Ross lens open using a locking cable release.

You then have an image plane you can focus the digital camera on, I used a Sigma AF Macro 2.8/50 on my a850, it was easy to just take a single shot, capturing the whole of the 5x7 frame to get a 24mp image, this was with a dark cloth in place, with me simply holding the a850 and having my head under the cloth.

The next step in sophistication is to make a device to mount the camera on that allows lateral and vertical movements, then you can take several exposures and stitch them together in photoshop. I believe come of the LF manufacturers may well have made such a device.


PostPosted: Thu Feb 08, 2018 2:11 am    Post subject: Reply with quote

Thank you, fellows, for your input. The whole discussion with your precisions gives a better sense to the article and gives some inventor's adrenaline.

Several years ago I was tempted to put a Sony Nex on the back of a MF camera to get a "vintage" look of the shots. Some of you wrote that you already did a thing of the kind. I did not advance much in the project later, after having tried some tests shots. They showed to me that the old lens did not shoot "vintage", it gave an "ordinary", good quality look to the image, if you make an imaginary correction of the undesired stray light effects produced by such "freelensing".

The idea to abandon one-sensor system and to use the matte screen as the second sensor to enlarge the DOF seems to give quite a different option. You explain well that a special glass is needed and probably a shift adapter is required even with the digital camera installed on the center axis.

I do not have an old MF camera now by the hand. But much later, in a sunny shiny day, I wish to try it, just to have an idea, with its ordinary matte glass and Nex equipped with a rather wide and close focusing lens. Something like Sigma Mini-Wide 28? Too curious about what may come out from the center of the matte glass.

Markus, Michael, thank you for your samples. Very interesting. Please, fellows, share more of your examples that give a better idea of the performance of your experimental equipment.


PostPosted: Thu Feb 08, 2018 2:54 am    Post subject: Reply with quote

Sometimes I also like this vintage look produced by these old LF cameras more than 100 years ago.
However, it's possible with much lesser effort to reach a similar goal with present day equipment and without LF camera:



A FF DSLR with a 85mm/F1.4 lens and a little bit of post processing. That's all.

What do you think about?


PostPosted: Thu Feb 08, 2018 8:26 pm    Post subject: Reply with quote

That's a good shot, and it is of course a fine lens.


PostPosted: Thu Feb 08, 2018 8:36 pm    Post subject: Reply with quote

What the fellow did is a supersized version of these things -

http://www.letus35.com/dof-adapter/

https://beastgrip.com/products/beastgrip-dof-adapter

The same idea - they mount 35mm lenses to project their images on a groundglass, which are then recorded by a camera with a small sensor (iphone, etc.) or dedicated videocameras.

Because these things have small sensors and so very short FL lenses, they can't do shallow DOF.
So this is a workaround.

The complications -
- Dirt, imperfections in the groundglass, which is difficult to make perfectly smooth and with no grain - this sort of thing will show up very well indeed as the camera lens will be focused on the glass itself. So the sophisticated versions (the letus ones for instance) have a vibrating or rotating groundglass, to make the image smoother.
- Close focus but with enough of a wide angle to take in the whole groundglass. Most of these things incorporate a close focus filter.
- Reversed image. Some of these have prism to rectify the image.


PostPosted: Fri Feb 09, 2018 1:30 pm    Post subject: Reply with quote

luisalegria wrote:
That's a good shot, and it is of course a fine lens.


Thank you! Indeed, the Minolta 85/1.4 is one of my most favorite lenses.

I've just ordered a Forex print 75x50 cm for that picture. Very curios about the outcome.


PostPosted: Sat Feb 10, 2018 12:10 am    Post subject: Reply with quote

Somehow I missed the article the OP is referring to.

Lovely shots.


PostPosted: Sat Feb 10, 2018 12:51 pm    Post subject: Reply with quote

luisalegria wrote:
What the fellow did is a supersized version of these things -

http://www.letus35.com/dof-adapter/

https://beastgrip.com/products/beastgrip-dof-adapter

The same idea - they mount 35mm lenses to project their images on a groundglass, which are then recorded by a camera with a small sensor (iphone, etc.) or dedicated videocameras.

Because these things have small sensors and so very short FL lenses, they can't do shallow DOF.
So this is a workaround.

The complications -
- Dirt, imperfections in the groundglass, which is difficult to make perfectly smooth and with no grain - this sort of thing will show up very well indeed as the camera lens will be focused on the glass itself. So the sophisticated versions (the letus ones for instance) have a vibrating or rotating groundglass, to make the image smoother.
- Close focus but with enough of a wide angle to take in the whole groundglass. Most of these things incorporate a close focus filter.
- Reversed image. Some of these have prism to rectify the image.


Yes indeed, those were developed quite a while ago and the Letus was quite a clever on. Very expensive in its days though.


PostPosted: Sat Feb 10, 2018 12:52 pm    Post subject: Reply with quote

ZoneV wrote:
I do basically the same since 2016, but on a larger inter image format and still in prototype stage.
I work up to now with a epidiascope lens 480mm f/3.8 at ideally crop 0.1:

Portrait by Markus, auf Flickr

Bearded-Man by Markus, auf Flickr

After a bigger renovation in our flat, I can now start working on the real deal, to get my camera moveable (without a car).


Excellent work Markus, I hope you keep us posted about your progress!
Appears as it won't be a portable solution though...