Pixels Visible Scanning with DSLR and Tablet

As a bit of background, I jumped into medium format with my first camera, first roll doing all the developing and scanning myself. Unfortunately, the camera had some issues that necessitated returning it, but in preparation for my next camera, I wanted to work on my scanning technique.

 

For this first try, I used my Canon 6D, a 100mm f/2.8L Macro lens, and a Samsung Tab A as a light source. The process worked well, except that when I zoom in at a 1:1 crop, the pixels of the Samsung Tab A are visible.

 

I've seen suggestions of using Apple tablets and possibly newer Samsung Galaxy phones for light tables. Is this a symptom of the specific tablet I used, or is there a way to prevent this?

You need a lightbox to review your film anyway. Porta-Trace / Gagne 8x10" LED ABS Plastic Light Box (White)

+1 on a lightbox--any LCD screen will show a pattern like what you have shown here.

A white translucent plastic diffuser might help (stuff used to make backlit signs and such). Another possibility if the screen is larger than the negative is to add space between the LCD screen and the negative so the screen is grossly out of focus when the lens is focused on the negative. The iPhone/iPad screens are quite impressive (I have one of each), but there is still a grid pattern. I have loosely considered doing what you're attempting, but haven't gotten to the point of a serious feasibility study

Thanks for the suggestions. I'm trying to avoid spending more money, but I may have to. My next attempt will be to build a lego box. My thought is to have the tablet, a flash, or an LED hotshot light I have on the bottom, a diffuser of some sort a few Lego stages up, then place the negative holder a few higher. If that fails, I guess a ommercial light box it is...

 

I wish I had bought the Digitaliza negative holder instead of the one I bought. It seems that a negative holder is better than glass, but this one doesn't hold the negatives particularly flat...

My thought is to have the tablet, a flash, or an LED hotshot light I have on the bottom, a diffuser of some sort

Well, I did almost exactly that, except that I used a cardboard box instead of Lego, with a sheet of opaque plastic across the top as a diffuser. I first just used a small day light fluorescent tube in the bottom, with a reflector made of kitchen foil stuck to a curved piece of card. I was getting quite long exposures which was OK as I had the camera on a copy stand. I later added a flashgun, poked through a hole in the side, which gave me a lot more flexibility in setting small apertures. Also flash has a defined colour temperature easy to set the white balance for. It sound a little rough and ready but I was surprised how even the illumination was across the diffuser surface, even for large glass plate negatives. It's good to mask outside the area of the negative using black card or similar, to cut out stray light and avoid flare.

 

(The smaller the aperture, critical focusing is easier and you are less likely to have focus problems caused by the film not being quite flat).

Edited January 19, 2020 by John Seaman

The Lego idea kinda worked. I used white legos and wax paper as a diffuser with the flash firing from the side. There was something off, though, I think. Maybe I just needed to work on the exposure. In any case, I decided to send back the film holder to Amazon, buy a Digitaliza film holder, and the lightbox Henricvs recommended.

Do what you can to diffuse the light source. I’ve seen people cut a piece off a translucent white plastic bag to put under the film or raise the film far enough off the tablet that the pixels are out of focus. (A light box is better, but if you don’t want to buy more stuff you make do with what you got.)

4 bricks, some frosted or opal glass or plastic, and a couple of gooseneck lamps

A bit of glass or perspex (plexiglass), a piece of white card at 45 degrees underneath it, and a flash pointed at the card.

Job done, with no pixel squares to get rid of.

 

There's an issue with a not-very-bright continuous source, and that's ambient light reflecting off the top of the slide or negative and ruining contrast or colour balance. Whereas flash, synchronised at 1/200th second or thereabouts, is hundreds of times brighter than any ambient room lighting and easily swamps any reflections.

I think that was the issue with my lego setup, despite using a flash.

 

That being said, I assume that with both a lightbox and a flash setup, that can be resolved by working in a dimly lit room, correct?

 

Mainly, the Lego solution was just unwieldy and awkward.

 

In any case, my wife didn't kill me when I told her about the lightbox purchase, so I figure I can keep it.