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Fourth question from me about this topic.

I'm trying to digitize a large number of family slide films with a modified slide projector by taking photos of the slides (I replaced the original yellow light bulb by a cheap cool white 50W LED).

I'm using a Nikon D5000 with a 55-200mm lens that I reversed using a reverse ring.

I'm able to get quite decent shots (in manual mode of course) however my focusing process can really be improved I think

  • When looking through the built-in viewfinder I only see blurry colors
  • When watching the live view with the camera screen I can't see anything very sharp (but still better than the viewfinder).
  • When plugging the camera to my computer and using DigiCamControl to check the live view it's also quite blurry

Only once I take the shot I can see a clearer picture. So when I set up everything to digitize some slides I always have to guess where's the sharpest point, take several pictures and compare them to see which one is at the end the sharpest one.

Is there any way I can improve that? I really would like to be able to see through the built-in viewfinder directly to determine the exact sharpest spot.

Thanks for your answers

Jérôme MEVEL
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  • I've never used a reversing ring, only ever extension tubes, but I'm surprised you can't see your resulting focus before you take the shot. [My answer to your last question assumed live view would be fine, even if it was a bit hard to squint through the viewfinder] – Tetsujin Nov 13 '20 at 16:09
  • I wonder whether it would be worth turning the lens round & using extensions. This is what I use & can focus before I take the shot. https://www.ebay.co.uk/itm/Meike-MK-N-AF-B-Auto-Focus-AF-Macro-Extension-Tube-Set-for-Nikon-DSLR-Camera-UK/312488980815?hash=item48c1cb714f:g:yTcAAOSwntRcbPht [I can't put this in an anser because I don't know why the reversed lens doesn't work] – Tetsujin Nov 13 '20 at 16:12
  • Late thought - Does your reverse ring have electrical connections to the lens? – Tetsujin Nov 13 '20 at 16:17
  • @Tetsujin Not very likely: https://expertphotography.com/wp-content/uploads/2019/01/reversing-rings-dslr-camera.jpg – chili555 Nov 13 '20 at 16:31
  • hmm… seems to be a rare thing. I'd dump it & go extensions instead. [I ought put this as an answer, but I'd like to be certain there's no electrical contact first] Ref: https://photo.stackexchange.com/questions/20381/how-can-one-use-a-reversing-ring-with-nikon-g-lenses & others – Tetsujin Nov 13 '20 at 16:36
  • @Tetsujin I'm using a Fotodiox Reverse Mount Adapter Ring which is a very basic reverse ring without any electrical contact. I actually have an extension tube which I never used because I always thought a Macro reverse ring would be better. I'll give a try when I've a moment. But in any case the viewfinder issue is annoying because I'd like to try to take macro shots about other things. I didn't search yet how a built-in viewfinder works but I thought it's only a simple mirror directly reflecting what the lens sees... – Jérôme MEVEL Nov 13 '20 at 17:32
  • Just to be clear, you are projecting the slides through the projector, and instead of imaging them onto a screen or wall, you're trying to project them into the camera (via reverse-mounted lens)? And when you say "a large number of family slide films", how many is large? Hundreds, thousands, tens of thousands? – scottbb Nov 14 '20 at 02:18
  • I there a lens on the projector between the slide and the camera lens? Does the projector have an "autofocus" feature? (some slide projectors do, but it likely would not work with the mirror/viewfinder but might work with the camera's sensor when the mirror flips up out of the way?) – Michael C Nov 14 '20 at 03:24
  • @MichaelC - there's a pic of the setup from the OP's first question on this journey - https://photo.stackexchange.com/q/116848/57929 which looks like direct focus onto the slide surface itself. – Tetsujin Nov 14 '20 at 17:04
  • Yes exactly, I'm projecting the slides directly to the reverse-mounted camera lens. I'm really busy recently but I quickly tried the extension tubes and even extension tube + reverse ring but I'm never able to properly focus. I'll keep you guys updated when I've more time for that project. And with just my parents' slides we already have a few thousand but then I'm planning to digitize my grandpa ans uncle's ones too. That will sure be way more than ten thousands in total – Jérôme MEVEL Nov 14 '20 at 20:39

2 Answers2

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If you achieve proper focus you will be able to see a clear image in both your optical viewfinder and your Live View display.

The fact that you don't see a clear image is just because you do not have proper focus. It is just blind luck that when you take the photo, you see a slightly better image, and that is probably just due to Depth of Field.

Most people reverse shorter focal length lenses like a 50mm for Macro work. My guess is you are too far away from the subject when using your 55-200 lens. Try shooting it at 55mm and move the lens closer so it is almost touching, and then very carefully increase the shooting distance until the image is clear in both your optical viewfinder and live View display.

If you are still not able to achieve sharp focus, it is because the focus point is actually inside the lens, and it will be impossible to use that lens reversed.

Mike Sowsun
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  • After a pause of one year on this project, I'm finally back to it. Back to the basics I successfully focused on a random object and was able to see a clear picture both through the built-in viewfinder and the live view on the camera screen. However for some reason when I try to do the same with my slide projector I still can only see blurry colors through the built-in viewfinder. Thankfully with the camera screen I'm now able to find the focus point however I must say it's not the best but much better than before! Thanks for your answer – Jérôme MEVEL Dec 04 '21 at 20:12
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In general, the best way to focus when using a reverser ring is to focus the lens at infinity, point the camera at your target, and then move the whole camera/lens assembly towards or away from your target until it comes into sharpest focus. This should be roughly at the lens' focal length from the optical center of the lens (which is not necessarily at the front of the lens).

Keep in mind that the camera must be perfectly square with the slide for the entire frame to be equally in focus. That is, the plane of the slide and the plane of the camera's sensor should be parallel, so that all four corners of each are the same distance from all four corners of the other.

Michael C
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