discussions on digital backs

[jtvr]

a good digital back is like a drum scanner with a lense.how come i don't find any discussions on use of lage format digital backs?

I started working with Phase one P45 about two years ago. after lots of experience, I notice my working has become equivalent to working previously with large format.

Anybody who wants to share thoughts on difference in use between digital backs and analog large format camera's?

[Chris Strobel]

Probably cause most of us here cannot afford a digital back, so no need discussing :) If I need that kind of resolution, I just mount my 5DII on my nodal head and shoot a quick multi-row pano.Autopano Giga software makes the stitching quick and easy.I have many shots in the gigapixel range that even a P65 couldn't touch, unless of course you shoot the P65 the same way :) But in the end I still prefer the look of film.If someone wants to give me a large format back though, I'd be willing to discuss it, and put it up against my 8x10 sheet film for comparison :D

[Kirk Gittings]

The Phase One P45 is capable of extraordinary detail and subtlety. A truly fine piece of equipment. But a P45 back in and of itself would not be considered large format here and would only be considered for discussion if used if used on a View Camera. Otherwise it is a lounge topic.

"The purpose of the forum is to provide a place for discussion of topics of particular interest to large format photographers. We especially encourage questions which will help build a repository of knowledge about the tools and techniques of large format photography, as opposed to "shopping" questions. For the purposes of this forum, we define "large format" as being essentially 4x5, or larger, sheet film. We do, however, allow what would otherwise be considered "medium format" sizes, IF exposed in a view camera (e.g. with a roll-film adapter), technical, or old-style press camera (e.g. the various Graphic cameras)."

[jtvr]

thank you for your reply mr. Gittings.

I am too serious to be involved in lounge topics.

I have struggled with the P45 back since I had it, for two years.
And however I am not actively involved in creating albumen prints or producing my own glass negatives, I still feel very much connected to the medium.

My point is that it is not only about the use of chemicals or not, and it is neither a matter of having medium format or 8"x10". It is about how you deal with your camera in relation to the environment in which you create a photographic image.

That is why I think that this is an appropriate topic to discuss in this chapter(?) "on photogrpahy". I think knowledge on large format photography goes beyond the use of a big camera.

[Robert Hughes]

Don't feed the trolls.

[Kirk Gittings]

jtvr,

Sorry, but those are the policies of the forum. They have been discussed to death on the forum amongst the members and amongst the moderators (including many times recently for both) and are not likely to change anytime soon. The above statement I quoted is the standing policy of the forum now and for the foreseeable future.

As far as being "too serious" for the lounge.......I "seriously" doubt that you are any more serious than I am and I don't hesitate to post in the lounge when my topic doesn't fit the guidelines for the main forum.

[Peter De Smidt]

I've used a Phase back on a Sinar P2. The digital back requires more precise movements than LF film, which explains the need for the P3. The lenses for the digital back need to be wider to give the same image as would be gotten on 4x5 film, and the digital back puts more demands on the lens. In other words, some lenses that work fine with film don't work so well with the digital back. Finally, using tilt and swing can cause color shifts and other issues on the digital backs.

[pdmoylan]

Peter, your comments on lenses suitable/unsuitable for use with a P45 caught my attention. Other than lenses manufactured specifically for, can you make a broad statement about which modern coated LF lenses function well with the back? Are there particular lenses which work well for you?

[rdenney]

Peter, your comments on lenses suitable/unsuitable for use with a P45 caught my attention. Other than lenses manufactured specifically for, can you make a broad statement about which modern coated LF lenses function well with the back? Are there particular lenses which work well for you?

I think Peter meant that the smaller format requires shorter lenses, and the greater enlargement ratios require lenses with better performance. The shorter lenses also require finer movements of the camera.

And digital solutions that use small-format digital bodies place the sensor deep into the camera with respect to the lens to provide room for a reflex mirror. That requires lenses of retrofocus design. Some digital sensors benefit from the retrofocus design even if it isn't mechanically needed, to aim the image light more directly at the sensor sites.

And digital sensors have different MTF characteristics, and introduce potential aliasing problems. Lenses optimized for digital backs are often designed to provide a different MTF at different spatial frequencies to improve performance with respect to these issues.

But it is certainly possible to get excellent images using digital backs and conventional high-quality large-format lenses.

Rick "who wants a 4x5 digital solution, but who can't afford any likely possibilities" Denney

[Bob Salomon]

Peter, your comments on lenses suitable/unsuitable for use with a P45 caught my attention. Other than lenses manufactured specifically for, can you make a broad statement about which modern coated LF lenses function well with the back? Are there particular lenses which work well for you?

Technically no Large format lens will work optimally as the sensor requires that the rays illuminate the pixels fully and the rays passing through a digital lens strike the pixels at a different angle then the rays passing through a large format lens. In addition, digital lenses may use the cover glass over the sensor as the last element in the optical formula.

You may want to read the technical differences in the lens requirements here

http://www.rodenstock-photo.com/mediabase/original/e_Rodenstock_Digital_Lenses_3-26__8236.pdf

[Steve M Hostetter]

I made a nikon to sinar adapter so I could do digital shot with the LF.. The shots I made were stitched and the finished images lacked sharpness..
I think the scanning backs work better with LF since they have a 4x5 scanning area

[Peter De Smidt]

We used mainly 100mm APO Symmars, and they worked ok, but our wider Super Angulons didn't perform very well. I think we tried the 47mm, 58mm, 72mm ones. The biggest problem was that there wasn't any real benefit for us over using the DBs on Hassleblads, and there was a big increase in weight, complexity and clunkiness with the P2. Please don't get me wrong. The P2 is my favorite film camera, but in our case it wasn't worth using it with our DBs. An Arca M wasn't any better.

[Don Dudenbostel]

Jan I have a Hasselblad CFV39 back and purchased it mainly to use on my Technikardan 23. I'm waiting for the correct adapter to interface the two but have shot with it using one of the adapters and have been quite pleased using conventional view lenses. The adapter I received made it difficult to use my 47mm SA XL but was able to use my 58mm xl and longer lenses. I do architectural interiors and exteriors and studio product work. I used film for the first 30 years of my career and have used digital for the past twelve or so years. I used a Dycomed scanning back in the beginning and never had a problem with standard lenses. At that time that was all there was and they worked very well. The CFV39 back also works quite well with everything I've I've used so far and the additional control of the view camera is a major plus over using the back on the hasselblads for product and architectural work. Even the 58mm XL works well with the use of the lens correction tool in the Phocus software. It corrects for the vignetting, chromatic errors and color shifts at the edges of the frame. It's a non issue in my opinion.

Performance wise it's superb as to color, dynamic range and resolution. Te beauty of digital for my work is vs transparency film is a no brainer. Digital capture is much more linear vs film. The curves for film are part of the design of the film and can't be altered to any great degree. (color transparencies) Digital raw files can be altered to create your own emulsion. The look of a well managed digital file is not "digital" looking unless you want it to be. The cfv39 back has a 12 stop dynamic range. What color transparency film has more than 6 or 7 stops? At 50 ISO there's no noise / grain and even at 100 or 200 ISO. There's no need to find a lab and you never have fees or any worry about the lab destroying your film or it ever being lost in the mail. No x-ray worries when traveling either. Native digital file sizes are larger than most cameras film size. I know the arguments but I feel a file that has a native image size of 18x24 inches is the equivalent of an original piece of film that size. Both film and digital lose quality as they are enlarged so I don't feel that's an argument.

Don't get me wrong I still love film but I also see digital as a fantastic tool with many advantages and few disadvantages. When you get into the quality level of the CFV39 and Phase backs film has a hard time competing. Just my opinion.