At 1:1 your angle of view is one-half that of infinity. Your shakes will be twice as noticeable. You will use a shutter speed twice as quick.
Ic, tremor is only part of the problem. Subject movement is also a killer because of motion blur (flash eliminates this) and movement of the plane of best focus, sometimes of the whole subject, between the time the decision to shoot is made and the time the shot is taken.
Most of my flower shots on 2x3 -- usually taken with a 2x3 Graphic on focusing rail on tripod and, yes, flash lighting -- fail because the plane of best focus moves between the time I finish focusing and composing and the time I take the shot. Remember, I have to close the leaf shutter, stop down (not necessary with all of my shutters), insert the film holder, and pull the dark slide before I can shoot. Wind is a killer.
Most of my flower shots on 24x36 -- usually taken with a Nikon SLR and flash -- come out because little time elapses between focusing and composing and shooting. Shots of fish that won't stop moving -- same gear -- often fail because I'm not quick enough/don't anticipate where the subject will be etc. well enough.
From my perspective most of the posts in this thread have an other-worldly air. I can't help wondering how many of the posters have done much closeup work.
at 1:1, 105mm f/2.8, i usually get away with 1/60th of a second. dont let the naysayers get you down. keep you eye on the moving focus and be aware of the direction of your shaking before you press the shutter
Well here are some pictures from the macro shots, no tripod or flash, IIRC these are at 1/500. Seems pretty alright to me, except that subject motion is another factor I have to consider and the compensation when going to 1:1. Is there a Macro lens that stays pretty much in one aperture, say f2.8, even when it goes to 1:1?
Most(all?) macro lenses are fixed maximum aperture.
What changes at 1:1 is the extension between the optics and the film. You lose two stops and there's nothing that can be done. It's a law of physics, AKA science stuff. Also, if you break the law, you may get a ticket.;P
So, Tripod for stability or light(to use a higher shutter speed.) to stop subject movement.
This one will work too. build a wind break to put around the subject. A diffuse cloth and four pieces of dowel to stick in the ground.
For one side those corrugated plastic sign that are all over the roadside..cheap, but it's illegal to just take them.