digital back for large format cameras

[shagen]

I been a lg shooter for years, this last year I broke down and got a

35mm digital camera. I love it but woould really like to do it with

my large format cameras. I just started to do research and I am

totally confused. while that is fairly normal I thought I might ask

some questions here because I am not finding much information out

there on them.

First off, does it really take 30 plus seconds to take a shot? If

so, why does it take so long? I can shoot a 35mm digital camera

basically the same way I shoot a 35mm film camera. I might be nieve

but I was thinking hey I could just slide in a digital back the same

as a film back and shoot away.

Secondly, some appear that you have to have them hooked up to a pc,

while others appear to have a built in hard drive to store images

till you can hook them up to a pc.

Third, if anyone can provide me with links etc. for me to learn I

would appreciate it. I poked around on many sites but realy didn't

find much information.

Thanks for any and all responses.

[vivek iyer]

The DSLR you use uses a single shot image capturing sensor which is more like film.

 

The LF backs are scanning backs which operate very much like a flat bed scanner. This is the reason for the 30 odd second time for each capture.

Inspite of this, they are are expensive. If these have to be replaced by digital imagers capable of single exposure capture (as in your DSLR), the cost would be just horrendous. Perhaps, in the next 10-20 years, there will be such imaging backs available.

 

As for the PC hook up is concerned, it depends on the image (file size). Larger ones need a computer with very large storage capacity to store the captured image.

[brian yarvin]

Steve:

 

When you get that big, digital breaks into two catagories:

 

1)single shot

 

2)scanning back

 

Single shot backs are made for medium format cameras with interchangeable backs and can fit on view cameras with an adapter. If you put them on a non-electronic camera, they can fire from the flash sync. My forty year old Hasselblads work fine this way. Speed is about the same as with 120 film. Modern units can write to CF cards.

 

Link - http://www.phaseone.com

 

Scanning backs are tiny high resolution scanners in the shape of a 4x5 film holder. They do take a long time (sometimes ten minutes or more) to do their job because they're scanners, not large sensors. Like anything else that's uniquely large format, the quality is astounding, but you will need an external control box and/or tethering to a computer. Scanning backs have been in widespread use for over a decade and are fairly easy to find second hand.

 

Link - http://www.betterlight.com

[greg lockrey]

Check this site out.

http://horsemanusa.com/digital/LD.html

[trw]

If you want digital images from 4x5, shooting film and scanning later is probably better for everything but studio still life. Scanners like the Epson 4990 and Canon 9950f are available for about $600 CDN, and there are lots of bureaux that will do drum scans.

[shagen]

WOW! thanks for all the excellent responses and so fast! This group is an excellent resource I should tap into more often. I now feel edumacated and not quiet so dense.

The difference between scanning and instant makes much more sense to me now. I kept wondering what they meant by first scan etc. but I failed to make the connection.

It does make more sense to invest in a good flat bed scanner (I have one already) and I thank you for the links. As I said I was just nieve but I could see a single shot sensor that big costing a kings ransom.

As with all computer technology I am sure the price and availability will continue to turn in the consumers favor.

I won't be getting rid of my beloved 4x5 any time soon. Although I am thinking of putting my 8x10 up for sale.

Thanks to all for contributing to my education.

[andy_shand1]

also with large format digital backs ..they are too small like 6x6cm size. This will make all your lenses much longer.The only true 4x5 digital backs in black and white only are in expreminental medical research. Apart from the huge cost to manufacture a true 4x5 capture back is the fact that they just get too hot at that size.However I am sure one day it will happen at a price we can afford but will we be alive to see it?

[michael_chmilar]

Your lenses do NOT "get longer". They are exactly the same size they always were. However, the capture area of the scanning backs is smaller than 4x5 film, so you capture a narrower field of view for each lens. The effect is the same as cropping your 4x5 film images.

[andy_shand1]

you mean my lenses arent acctually longer?...thats a relief.

[kelly_flanigan1]

4x5 scan backs have been around for over a decade. "The obsolete" Phase One I use is only 35 Megapixels. The tethered computer requirements are modest. My rig was specified as requiring a Pentium at least 90Mhz. In practice I use several different boxes. An Old 200Mhz Pentium Pro with 512Megs of ram and Windows 2000 has the task manager running at 5 to 10 percent during a scan; the box is overkill. The added ram allows ample room for the 105meg files; for simple stuff. For anything more the image is moved on the LAN to a modern P4 with 2 gig of ram. <BR><BR><BR>These Phase One 4x5 digital backs are thicker than a regular filmholder. BUT mine does work still with my pre WW2 speed graphic with spring back too. Many of these backs are/were used in studios for product shots; and print shops for "shooting artwork". One has quick feedback; and one dosnt have to screw around with a dying senile lab that muffs up ones chromes. This is the MAIN reason I made the plunge long ago; control and quality..<BR><BR>A workflow might be setting up your 4x5 camera; adjusting the lighting; composing the image on the ground glass and focusing. Then the digital back is inserted; cables hooked up. A quick prescan is done; and a white balance done; usually on a known neutral grey object. With the Phase One here one places a software eyedropper on the "to be grey" part of the image; and forces it to be neutral. My rig requires an Infrared filter over the lens; this is in place during all exposures. One can check for clipping of the highlights; and adjust exposure and the lights to get a good image capture. The highlights and shadows in a product shot are checked; and lighting changed if required.<BR><BR> The taking lens in open; ie on bulb ot time exposure. One can get better focus than a film situation; one can do prescans and critically get focus at the working aperture. There is no film buldge; no tolerances; no focus shift to worry about. If there is dirt on the scan bar; then horizonal colroed bands will appear. The scan time is long ; many minutes for a full res scan. The real active scan area is 7x10cm on then old Phase One here. These were about say 50k when the first came out; then down to 35k; the down to 10 to 2k on the used markets. With the large effective pixel size of 14 microns; the noise is super low; and lens requirements modest.

[andy_shand1]

you know ..if a scan back could be picked up for 2k...well that might be worth it just to play around with it. Problem is you cant use it outside on location which is what most of my work entails if your working by yourself. Also if your shooting in the canging evening light ..i suppose you could scan from bottom to top.. it would be like using a gradient nd filter.

[kelly_flanigan1]

Here is a Phase One 4x5 scan with a 150mm F9 APO Ronar process lens; at not the full resolution; with full the 7x10cm "frame" and details. The camera body is just an old 4x5 Speed graphic. This is a barrel lens.<BR><BR>One can make a fine image with no film; a surplus lens; and a pre WW2 press camera. The backs are expensive.<BR><BR><img src="http://i4.photobucket.com/albums/y148/ektar/150mmRonar/Ronar150mmFull.jpg"><BR><BR><img src="http://i4.photobucket.com/albums/y148/ektar/150mmRonar/Ronar150mmStones.jpg"><BR><BR><img src="http://i4.photobucket.com/albums/y148/ektar/150mmRonar/Ronar150mmWWVCLOCK.jpg"><BR><BR><img src="http://i4.photobucket.com/albums/y148/ektar/150mmRonar/Ronar150mmDOG.jpg">

[kelly_flanigan1]

Without the IR filter on the taking lens; the old Phase One 4x5 digital back has alot of IR response. Here is a shot without a filter; using an surplus 178mm F2.5 Kodak Aero Ektar I bought for 5 bucks long ago. Being corrected for IR; this WW2 lens is sharper than the scan back at F11. <BR><BR><img src="http://i4.photobucket.com/albums/y148/ektar/scanback/SpeedGraphicF11AEsmall.jpg"><BR><BR><img src="http://i4.photobucket.com/albums/y148/ektar/scanback/SpeedGraphicF11AEmed.jpg"><BR><BR><img src="http://i4.photobucket.com/albums/y148/ektar/scanback/SpeedGraphicF11AEdetail.jpg">

[kelly_flanigan1]

Andy; the limit for working outdoors is subject movement. These scan backs can shoot a fine building; but trees limb ends and people will be blurred. An old laptop with a SCSI card works just fine. About 5% of the images I shoot are outdoors with this rig. There is no chromes to send away to wait a week; no drum scans to farm out. This saves about 10 business days on a project.

[andy_shand1]

looks great although the colour spectrum (not ir ones) seems a bit odd...do these generate full 16bit files? Acctually for architecture movement might not be such a problem and the ir response could be great for some schulman type shots. Might even cut through the pollution in this part of the world.

[andy_shand1]

just done an autolevels on it..its seems much better now.

[andy_shand1]

saw one on ebay for 800 dollars but it seemed quite low res like 2500 x 3600?

[victoria_trudeau]

Look for information on Phase One p45 back. Its very expensive, but it sure has its

advantages. And it is aompatible with 4x5 cameras. The first is a link to phase one site,

and the second is a link to a review. The third is a link to another very objective review,

wich compares 4x5 films and digital backs

 

You refered to 30 secs shots. Those are not digital backs, so I've read. Those are digital

scanners, that send information directly from your camera to a computer, wihout a

memory card.

 

Good luck

 

http://www.phaseone.com/Content/p1digitalbacks/Pplusseries/Introduction.aspx

 

http://www.phaseone.com/upload/reviewp30_p45.pdf

 

I think this ios a good basic review. It helped me a lot

http://www.luminous-landscape.com/essays/Cramer.shtml