Megapixel equivalent

[Stealth3kpl]

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I'm not familiar with the terminology in slide scanners. If I were scanning a 35mm slide with an Epson V700 at high res (6400dpi x Sub 9600dpi) does that mean the single slide is scanned at the equivalent of 60megapixels (or there abouts) or are all those megapixels shared out by the 12 slides in the holder, or have I got the wrong end of the stick?

Pete

[peterv]

That would be 60 MP per slide. Depends on a lot of parameters (film resolution, lens sharpness, film flatness, etc ) wether such a large scan would be usefull.

[adan]

If the scanner specs give you ppi resolution (pixels per inch), that does not correspond to any amount of Megapixelage - until and unless you also specify the film dimensions being scanned.

 

It's sort of like asking "My car does 100 kph - how long will it take to cross Country A?" Unless you know how far it is across Country A, the answer is still undefined.

 

35mm images are usually a bit smaller than 1" x 1.5", so one has to take that into account in calculations - more like .95" x 1.42". So while a scanner may deliver 6400 ppi, the actual scan dimension across the short side of the frame may really come out less than 6000 pixels.

 

E.G., my Nikon scanner does 4000 ppi, but that does not give me 24 Mpixels (4000 x 6000) from a 35mm slide. I really get 3788 x 5669 or thereabouts (21.5 Mpixels) of actual image.

 

But - to get back to your underlying question - once you know your resolution and your (real) image size - that will be per image. And 12 slides will be 12 times that much.

[Julian Thompson]

Well, I have the same scanner (the V750) and now I have managed to get Vuescan working well (really, really, really well in fact!) I am making use of these large scans. I have a 52 inch large format printer and in this case the big files print very well and stand up to viewing from impressively close distances (as long as my film choice in the first instance has a sensibly low grain level of course!) Bottom line is that with that scanner and some good film you can go big for sure! In my case I reduce all files to 'just' 20 megapixels in photoshop before I put them in Aperture as my library. This allows me loads of scope but If I do then need a simply massive big print and want absolutely the best my equipment will allow then I use my metadata to allow me to physically find the negative and do a rescan.