How Many Megapixels do I Need?

Hello,

I have 700 very precious slides of the work of a top Canadian visual artist. Ive been given permission to digitize these. Im happy to take this on. I do not have an unlimited budget. I will need to purchase a camera?

Was thinking of a 20-24 megapixel DSLR or mirrorless camera, likely Nikon, with ES-2 digitizing attachment.

My budget would be strained to get a top-of-line 45 megapixel camera like the D850 or Z7…but maybe it could be possible.

Would 20-24 megapixels “extract” most/all of the information on the slides?

(Later I have personal 35mm negs to digitize, mostly black and white)

Would 45 megapixels be hugely better?

How large could I print in each case?
How large a 4k TV screen could I fill in each case with a HD image?

If 20-25 megapixels would give great results, thats great.
If Im going to do all this work, and 45 megapixels would be HUGELY better, maybe Id better, somehow, get the cash for a better camera.

Would really appreciate your feedback.

Let’s look a at 24 mpixels. They usually come as 4’000 x 6’000 pixels.

  • If you print at 300 pixels/inch, 24 Mpixels will enable a 20 in wide print - iff you fill the frame.
  • 4k has up to 4096 pixels horizontally, which means that a 24 Mpixel shot overfills a 4k screen.

24 Mpixels should be enough for any but the highest resolution films. And you can always stitch a few shots for better resolution (for better visibility of grain)

Higher pixel count allows for less tight shooting without compromising quality.
If you buy a lens, check the specifications. Many macro lenses cannot do 1:1 without additional equipment like bellows or extension rings.

Search the forum for a whole lot more information on technical details.


I’ve used a Nikon D7100 (24 mp), D800 (36) and a D850 (46) for digitizing a variety of film sizes from 35mm to 5x7 in. Some points:

  1. The tests I’ve done with Kodachrome, Provia and Velvia 35mm slides show virtually no increase in real detail going from 24 to 36 mp. I think that 24 (4000x6000 pixels) more than covers the available resolution from 35mm slides. This roughly matches the resolution of Nikon slide scanners.
  2. On medium-format film, there definitely is an increase in detail going to 36 mp from 24. Using the D850 over the D800 on medium format gives a very small, almost negligible, advantage. I expected more, given the higher resolution and no low-pass filter.
  3. If you’re using a full-frame camera with a 1:1 macro lens, a small amount of the slide mount will show. This can be cropped out later, or just left to show that nothing was cropped out of the original (other than what’s hidden behind the slide mount). Using an APS-C sensor with a 1:1 macro lens, you can crop in tighter to avoid the slide mount showing, if desired.
  4. Use a good macro lens, such as the Nikkor 60 f2.8, which I presume you’re planning to use since you’re using the ES-2.
  5. Clean the slides well. If they have been previously scanned at service bureaus, or stored in less than optimal conditions, they will have likely have a lot of very small dirt specs. I remove these by pressing on 3M magic tape with my finger, then pulling it off. Don’t rub the tape across the surface of the slide or it will leave a residue. Compressed air will not generally remove these small, persistent dirt specs. You should get permission from the photographer before doing this.
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Hi I am currently in choosing new scanner or DSLR setup.

Thank you for your post very informative.

I have seen this video Do Megapixels Matter When Converting Negatives With A Digital Camera - YouTube that shows there is minimal difference between 24mp and 50mp. I was a little surprised when you wrote you see increase in details from 24 to 36. Is the difference you see similar to one in video or bigger?

Have you tried to scan medium format on scanners like Noritsu or Fuji and are the results better/worse/same than your DSLR?

thanks

I don’t think I saved those tests to compare 24 to 36 mp on medium format film (6x6), but I can do them again when I have the time. These were historical negatives and although the difference was not huge, it was noticeable. You probably wouldn’t see the difference in prints unless they were pretty large.

I had a Minolta Multi Scan Pro, which was 4800 ppi, other words almost identical to my D800 on the short side. It produced excellent scans, but for negatives or transparencies that needed a bit of image editing, the final results were better with the camera scan, because the raw files can be manipulated a lot more, especially with regards to tonal range, lifting shadows and adjusting colours. After comparing the Minolta scans to my camera scans I sold the Minolta.

Having been a professional photographer for a number of years, I have drum scans such as Linotype-Hells, of many of my transparencies and have compared these to my camera scans. After sharpening, the camera scans are just as good as the drum scans, and have the advantage of giving me the capability of manipulating the raw files to make a better final image. I also did some comparisons with a Hasselblad scanner and the camera scans were just as detailed.

The video mentioned mentioned grain. I haven’t noticed the grain being more obnoxious with medium format at 36 mp than 24, but haven’t really looked closely. I can’t figure out why that would be, other than the higher megapixels picking up more detail in general. I sometimes apply a small amount of noise reduction or contrast by level details to reduce film grain, but am careful not to overdo it.

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Interesting.

I’m thinking of upgrading my D750 for scanning. Trying to decide between a Z7 & a D810. You may have made my mind up for me :slight_smile: Might just get the D810 and save some cash. I can also keep using my 60/2.8 G.

I don’t really shoot much 135 anymore. Mainly 6x4.5, 6x6 and 6x9. The D810 has a few useful upgrades from the D750 for me … 900 more px vertically, no OLPF, Electronic First Curtain and a base ISO of 64. The D810 is a great bargain.

I hardly ever shoot any digital either so maybe the Z7 is a waste.

Cheers!

I tend to agree with that because you can buy a good used D810 these days for a decent price, and if you ever need to make a huge print, you can always stitch.
When using a DSLR instead of a mirrorless, make sure you use live view for accurate focusing. For critical focus work such as this I don’t trust just using AF fine tune. For instance, with my D800, my 60 f2.8D lens seems to focus accurately at a “0” setting, whereas my 60 f2.8G needs about “-20”, right at the end of the scale. Using live view eliminates these issues. I have a friend with a D810 and he also has significant variances in focus with different lenses.

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