Shutter speeds/focal length/handheld

Just wondering whether the standard formula for the minimum shutter speed you should use handheld also applies to medium format? I know on 35mm you really need to keep the shutter speed number higher than the focal length of the lens to avoid shake (so with a 500mm lens you need to be at least 1/500th if not higher), does this apply to MF too or are the numbers different?

It would be safe to do so.

However, being a larger format it should be affected less than 35mm or APS-C as you don't magnify the finished image as much.

The logic of this is sound, but larger formats are often used on a tripod anyway. I always found I could use a Rollefilex fairly safely at 1/8sec. but the Spotmatic was always at least 1/30sec with the standard lens.

Surely, the amount of shake is going to be less apparent on the medium format due to the field of view being larger for a give focal length?

Yep, but bear in mind that I would still like to be able to crop and enlarge the negatives. I want to get the old enlarger back into action as early attempts to scan negatives proved tedious and unsatisfactory - the scanner just can't cope with the resolution needed if you then plan to enlarge the results. Scanning A4-sized prints made the old way should be much better.

It sounds as if 1/125 with a 150mm or 200mm lens would be safe enough though?

It's all to do with magnification. At the other extreme a Minox is quite vulnerable to shake, despite what we see being achieved in all those spy movies.

It's fairly simple I think.

The height of a 135-format frame is 24mm. The height of a 645 frame is 45 mm. So where a 50mm lens on 135 requires (according to the "rule") a shutter speed of 1/50, on a 645 that would translate to 45/24 x 1/50 = 1/75 (approximately).

It's because 645 negs need 50% less enlarging than 135 negs.

On APS-C, the sensor height is 16.7mm, so the safe speed is 16.7/24 x 1/50 = 1/75.

G