Tips for finding the grain to focus on (w/ Fuji X-E4 / Nikkor 55mm f3.5 Ai / PK-13 extension tube)

Hi there,

I’m wondering if there are any specific tips for finding perfect focus on the film grain. I use a Fuji X-E4 (APS-C) with the Micro-Nikkor 55mm f3.5 Ai adapted along with the PK-13 adapter. The camera is mounted on a Negative Supply copy stand, and the film is run through the 35mm basic holder on top of their 99 CRI light source.

I’ve enabled focus peaking (Yellow, High) and it just seems so damn difficult to find that “perfect focus” on the film grain. I can’t tell if I move the focus a little one way or the other what’s more “accurate” in comparison tests I’ve run. Am I overthinking it? When do I know when it’s “good enough”? Where should I be looking in an image to find the best grain to focus on? The highlights or the shadows (aka, the denser part of the negative or vice versa)?

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Be sure emulsion faces the sensor. That puts the image directly in front of the lens. If film base faces lens, it acts as mild diffusion and softens the image.

Might be a stupid question, but how do I know which side is the Emulsion side? If I can read “Ilford HP5+” or the image numbers for example, is that the emulsion side?

Looking from the emulsion side the edge signing (‘Ilford’ etc) will be like mirror writing. The emulsion side is also less shiny.

Midtones are generally best for focusing. The brighter the light the easier it is. With a good lens (the micro Nikkor is one) focus doesn’t shift as you stop down so focus wide open & stop down for the exposure. You’ll be lucky if you find that the focus in the centre is the same as at the corners but that’s life. F8 is generally best but do your own tests.

I’m using autofocus on my setup and it’s quick and precise.

Adding to the above comments, if you can, set up your duping so you are focusing by moving the camera as a whole unit forward and backward toward the negative. You will see grain is much easier to lock onto than by adjusting the lens barrel alone. A micrometer driven close-up slider will make this easier. You can pick one of these up for around $100.00 if you don’t already have a way to do this. With this approach, the lens focus position is set for the magnification desired and focus is achieved moving the whole camera a little forward or backwards in relation to the film. Also have your live view on the back at least at 100% to confirm focus; if you can, go to 200% for spot checks. You can check your alignment by focusing a quarter of the way in from one edge and then shifting your live view to the opposite side to compare. Getting exact plano parallel alignment is the trickiest part of a set up such as you describe and it’s worth the effort to put the time in adjusting your setup until you get it right. Then it becomes much easier for all the other duping you do in the future.

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Moving the whole camera +lens assembly as a whole rather then focusing with lens is the very good advice. The reproduction scale is maintained and focus behave more “natural” and precise.


That target may be of help