50x Mitutoyo Q's

Beatsy · Post by **Beatsy** » Thu Aug 25, 2016 10:25 am

I've been playing around with a 10x mitty for a short while and I'm very, very impressed, especially as I can back it down to 5x using a 100mm tube lens (or 6.75x with 135mm). I thought I'd struggle to find many interesting subjects that fit the field of view, but that's not the case at all. Quite the reverse actually. I use a Canon MP-E 65 to get an overview then switch to the mitty for areas that appear to have more interesting detail at higher resolution. Great fun.

Trouble is - I now see things in 10x images that may have *even more* detail at *even higher* resolution. Of course, I want to look at that too!

So, inevitably, a higher power mitty is on my wishlist - already. I looked at the 20x, but for the money, resolution of 0.7um doesn't seem vastly better than the nominal 1.0um of the 10x. So, with resolution down to 0.5um, the Mitutoyo M Plan Apo 50/0.55 LWD must be the one for me - I think. A few questions before I sell a kidney to get one.

1. Can the 50x be run on a 135mm tube to give 33.75x? How about 100mm for 25x? I expect some image degradation at the edges of course, but if it can do 25x then that pushes the 20x right out of the running.

2. Does the 13mm working distance make diffuse lighting *that* much more difficult? I have a 150w fibre optic light source with a ring light at the moment. I was thinking of getting a bifurcated (dual) gooseneck fibre optic fitting for it. Will that be useful (with suitable diffusion)?

3. I assume depth of field is around 1-2um depending on tube lens length (because the circle of confusion shrinks on sensor at shorter tube focal lengths). Assuming a perfectly stable rail/camera setup, is it feasible to take individual 25x-50x stack shots using a hand-operated micrometer "adjuster"? Or would I need something more accurate? If so, what? (Note: I'm pretty sure the 4k video technique I posted about will work well with enough light. The question pertains to separately photographed frames only).

4. Anything I haven't considered?

Thanks

Charles Krebs · Post by **Charles Krebs** » Thu Aug 25, 2016 9:53 pm

camera format?

Beatsy · Post by **Beatsy** » Thu Aug 25, 2016 11:43 pm

Sony A7R2. FF mirrorless. Can be configured as APS-C (crop sensor format) if required though.

boomblurt · Post by **boomblurt** » Fri Aug 26, 2016 8:30 am

G'Day Beatsy.

I have both the Mitu 20/0.42 and the 50/0.55, but I haven't used either that much. However both cover my FF Canon 6D with the Raynox 250 (125mm) without vignetting and I've found the working distance fairly friendly for lighting and diffusion. As for your other questions, I use flash to minimize vibrations as my rig is vertical and the dangly bits (Stackshot/camera/tubes etc) wobble at that magnification.

Personally I find working at 50x quite a challenge and a good stage (mine has linear stages/goniometers with 6DoF) is essential imho.

Beatsy · Post by **Beatsy** » Fri Aug 26, 2016 8:57 am

That's very encouraging Boomblurt. I have a horizontal rail-based rig arriving soon. It has 1 rotating and 3 linear stages along with 2 goniometers for 6 DoF like yours. Camera body, lens and stages are all firmly clamped to an optical rail so I anticipate good stability - but flash is an option if needed. Thanks for your comment.