Digital Help
Q&A For Digital Photography

This column will attempt to provide solutions to problems readers may have in getting into and using digital cameras, scanning, and using digital photographic images with a computer and different kinds of software. All questions sent to me will be answered with the most appropriate information I can access and provide. However, not all questions and answers will appear in the column. Readers can send questions to me addressed to Shutterbug magazine, through the Shutterbug web site, directly via e-mail to: Fotografx@csi.com or by US Mail to: PO Box 2830, Lompoc, CA 93438.

Q. I subscribe to Shutterbug and have found your Digital Q&A section to be very helpful. I am a bit confused on one point and was hoping you could help clear things up for me.
I shoot primarily nature photos on transparency film. I have a 35mm system as well as a Mamiya 6 6x6 system. I have been having my slides scanned onto a Master PhotoCD at my pro lab and bringing them into Photoshop 5 on my Mac PowerPC. I have been adjusting the images in Photoshop (with the help of Extensis Intellihance). If I want to print them I can output the file to my desktop Epson Photo EX or take the file to the pro lab where they can print it using a Lightjet 5000.
I have been considering getting a slide scanner to use at home and it would seem that the Nikon 2000 has the best software. What puzzles me is the print size that you say you can get from your 35mm scans. I have read that to get "photo quality" digital output you really need to provide the printer with around 300ppi of data. I have also read that you can get away with sending around 240ppi of data to the Epson Photo EX without any significant degradation of image quality. My lab tells me that I should provide them with 305ppi for files destined for their Lightjet 5000 printer. Given these parameters how is it possible to get "excellent 11x14 prints" with the image file size generated by the Nikon 2000 scanner or PhotoCD? What resolution do you set your files at when you send them to the Epson printer? It would seem to me that you must use files at a lower ppi or somehow "pump up" the file size using an interpolation program. Which do you use? I know that there are interpolation plug-ins available for Photoshop, do you use one of these? What happens to image quality when you do this? I have the same question about the Nikon CoolPix 950 camera. Nikon claims that you can get a photo quality 11x14 print from their largest TIFF file size, but I don't see how this is possible.
Steve Rosenblum
Ann Arbor, MI

A. Printer resolution refers to the number of dots the printer lays down per inch and is unconnected entirely to how many pixels per inch are in the image being printed. Standards are not fixed as to what a printer needs in image resolution, and the high 1440dpi resolution of your Epson EX is no indication of the image ppi resolution required to make a good quality print. However to see the most detail a particular printer is able to reproduce there is an optimum image resolution, which with your Epson, is 240ppi or higher (you are right). That specification is for an image of about 8x10" printed on letter size paper. In practical terms with most images you can go as low as 180ppi in image resolution and still obtain quite good quality prints with little if any loss of image detail or sharpness.
Now consider if you increase the print size you also increase the normal viewing distance of a print. By doing so you reduce the necessity for defining detail as sharply because human vision cannot normally perceive that fine a resolution of image information at the greater distance. Thus the image ppi count can be lowered somewhat as print size is increased. For an 11x14 I would say 150-180ppi should yield acceptable image sharpness and detail definition for viewing at a normal distance.
So, now lets take a 35mm slide and scan it with the Nikon Super CoolScan 2000 at its maximum optical resolution of 2720. If you are scanning the full frame you should get an image that's roughly 2700x4000 pixels. Now if we are going to print it with an Epson Stylus Photo EX on 11" wide paper, then we size the image to 10.5" wide which will produce a .25" border on the sides of the print. When this image is so sized I think you will find the resolution is 257ppi. Well over the optimum level for the smaller, letter size print for which the 240ppi figure you referred to was given. In fact, I have taken image files scanned with the Nikon LS-2000 up to 13x19", and they look just as good if not better than I would expect of an "R" print made by a lab directly from the slide. Now, being that you referred to the Nikon LS-2000 and LaserSoft SilverFast 4 software driving it, please consider this software supports interpolation beyond the optical limit of 2720 to almost twice that, and over 5000ppi. It would be quite easy to output just about any practical print size up to and including 16x24 for printing by a service bureau that demands 305dpi.

Q. I have enjoyed reading and appreciate your thoughtful column in Shutterbug. The following question stumps me, but I hope it will not stump you.
I want to buy a digicam for under about $750 that has a wide angle lens which is the 35mm equivalent of 18-22mm so I can take pictures of sometimes small rooms inside cabins, etc., for The Colorado Directory of Cabins, Lodges, Country B&Bs, Campgrounds, and Fun Things To Do we've been publishing for 20 years and also for use on our web site at: www.col oradodirectory.com
So far the only thing I've found is the Kodak DC200 which will accept a 0.5 Tiffen add-on lens. Do you recommend it? I am not interested in stitching photos together to create a wider angle.
As our directory is printed on newsprint with a resolution no finer than 100dpi and as photos on the web are even courser, we don't need high resolution, although we may wish to crop occasionally. Ideally, we would like a 35mm equivalent of 20-80mm.
As we are a micro publisher and as we are on the road as of June 1 to begin our annual summer sales trips, we need to buy ASAP.
Can you help, please? Thank you.
Hilton Fitt-Peaster

A. I can appreciate the reasons for your need in a digital camera. And, you are probably not alone considering the real estate industry uses digital cameras so extensively. I'm sure the manufacturers would like to meet this demand. However, if you consider the very small physical dimensions of the CCD chips used, 1/3 to 1/2", and that the modest wide angle lenses for these cameras currently available are slightly under 10mm in focal length, anything shorter would involve some severe physical production challenges. The one most limiting factor would likely be making a shutter/aperture for a lens of any shorter focal length. It's not impossible but that kind of very precise micro manufacturing is also very expensive, and without extreme micro precision, the aperture accuracy and the optical imaging quality due to halation would suffer.
The only digital solutions that would be satisfactory unfortunately are several times your budget in cost. The use of a Tiffen filter adapter and an auxiliary lens I have not tried, but would have grave doubts it would be a satisfactory solution in terms of image quality and usability with anything other than an SLR like the Olympus D-620L. Personally, I still maintain a couple of Canon EOS systems with some short lenses and shoot color negative film. I proof it once processed, one whole roll at a time, with a flat-bed scanner with a TPU, and then use a slide scanner to scan the frames I want to reproduce. It's a very effective hybrid workflow, and minimizes processing costs as well as labor.

Q. Recently on a holiday I stumbled across a back issue of Shutterbug and was interested to read about the development of digital adapters which effectively turn basic 35mm SLRs into digitally enabled cameras. The article was in the December '98 issue and was contained within a feature on the photokina '98 exhibition.
Could you possibly tell me whether the adapters are available yet to "Joe Public," and if so where I could expect to purchase one here in the UK as well as what I should expect to pay? If they are as yet not available on the retail market, maybe you could point me in the appropriate direction for investigating things further such as recommended literature, etc., on such devices. Kind regards.
Matthew Pollard

A. Yours is a wish held by many, even myself, but unfortunately I know better. First you have to consider essentially what you are looking for is an inexpensive Kodak DCS 560, or at least the back and digital parts. That camera model costs as much as a new sports car, and personally I'd rather have the car. You can be assured, that if it were possible to produce a back for any of the major 35mm SLRs which would, 1) provide normal or close to normal lens functioning (angle of view), 2) have a chip resolution comparable to a scanned 35mm image, and 3) cost as little as you are hinting Joe Public could afford--Canon, Nikon, Olympus, Minolta, et al., would be the ones offering this kind of digital back for 35 SLRs at the next Photo Marketing Convention. The why of this is quite simple. CCD area array sensor chips cost far more to develop and involve a far larger manufacturing investment than any camera. In other words, it is less expensive to design and build a camera to fit the chips available than try to resolve the problem the other way around.

Q. I found your recent columns in relation to large volume digital slide storage and scanners very useful. My father recently died and had a huge number of slides dating back to the 1940s. I have purchased the Nikon LS2000 scanner and a CD writer drive. The SilverFast software will be ordered today.
My problem is that some of my siblings are not computer literate and just giving them a CD will be of little use. I will need, for these individuals, to get prints. I have an HP PhotoSmart printer and have seen the results of the Epson 700 and have wished for a good bit more in print quality from both of the printers. I wasn't thrilled with an HP 895 or upper end Epson. I have been told that until you reach the several thousand dollar range there is no better alternative to these two scanners. I have seen some digital prints that I like the quality of, just not these models. I hate paying over $10 per print for digital images locally and would like to have some control over the printing. I would appreciate any thoughts you might have on this topic.
Richard Saloom
Prattville, AL

A. From your remarks I am somewhat of the impression the prints you find inferior are not as good as the printers can produce, not because of the printer but due to characteristics of the image file reproduced.
I have been able to make prints with the Epson Stylus Photo 700 and EX which are definitely on par with typical photo lab "wet" color negative prints. And, in terms of just the reproduction of tonality and color, there is not a significant difference between the best ink jet prints and much more expensive dye sublimation prints. Of course there are other reasons to favor dye sublimation, like the speed of printing and the durability of the print.
But, regardless of what specific printer or what type, to obtain an optimum print result you must be reproducing from at least a close to perfect color corrected image file and be using a system that has Colorsync (Mac) or ICM 2.0 (Windows 98) color management fully implemented and functioning correctly. This is essentially the digital equivalent of the fact that even the best enlarger and print processor does not ensure good "wet" color prints, it also takes skill on the part of the operator as well as a good negative from which to print. For what it's worth, the current Epson Stylus Photo printers are being replaced with new models which produce even better results. The Epson Stylus Photo 750 is now just being shipped to some stores.

Q. What is the maximum usable resolution and color bit depth of films, like Ektachrome and Elite Chrome?
John Bastian
Vaparaiso, IN

A. In theory there is no maximum, but in practice of course there is. And, there is really no direct correlation between how most of us think about analog information in terms of resolution and the digital counterparts. In real terms the answers to these questions are involved in what your goals are in digitizing film images, and of that what you can afford. High-end scanners today are capable of reading and recording just about all of the useful information in a film image, and then some. Extremely high (up to 8000dpi optical) scan resolution is used not so much to extract more image information from a film photograph, but to record it with sufficient pixels to make a reproduction of a particular large size. So to one extent in determining scan resolution the output size is the determinate factor. From my experience a resolution much over 3200dpi does not yield increasing amounts of image information, and the 2700-2800 maximum resolution of consumer desktop 35mm scanners extract most of the image information from a 35mm Ektachrome image.
Bit depth of better film scanners is usually 12 per RGB channel, and in higher-end professional scanners 14 bit per RGB channel is common. Considering the computer only supports 8 bits per RGB channel, current scan depth is quite sufficient to be able to read even relatively narrow density range images and map them to fully utilize the gamut of the computer colorspace. In other words, better scanners are quite capable, if they have effective software support, to map all of the information in a film image which is possible to reproduce with the computer's 24-bit RGB colorspace.

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