Photographing a moth egg - advice please

Archibald wrote in post #18496375
Hint - shorter focal length will give more magnification.

So, are you suggesting that my wide-angle at, say 50mm, might be better, or only if reversed, please?

Trik

Trik wrote in post #18496359
I am unsure as to how they work as well - after each movement, I would need to re-focus. Is that correct?

No.

You achieve initial focus slightly in front of the subject. You never touch the lens afterward.
All subsequent focus changes are accomplished by moving the entire camera forward via the rail until you have an area slightly behind the subject in focus.

Archibald wrote in post #18496375
Hint - shorter focal length will give more magnification.

I get my greatest magnification from a 50mm Minolta manual reversed onto two sets of extension tubes.

I've been keeping my eye open for a bargain on another manual lens in something like the 28-35mm range.

Trik wrote in post #18496381
So, are you suggesting that my wide-angle at, say 50mm, might be better, or only if reversed, please?

Trik

extension / FL = reproduction scale...

As already suggested, use the SHORTEST AVAILABLE FL lens with a specific extension tube in order to obtain highest magnification of subject on focal plane

• 25mm extension on 100mm FL (focused at infinity) = 25/100 = 1/4 scale image
  
• 25mm extension on 50mm FL (focused at infinity) = 25/50 = 1/2 scale image
  
• 25mm extension on 25mm FL (focused at infinity) = 25/25 = 1/1 scale image
  

• 100mm extension on 100mm FL (focused at infinity) = 100/100 = 1/1 scale image at a distance of 400mm from subject to focal plane (4* true FL)
  
• 50mm extension on 50mm FL (focused at infinity) = 50/50 = 1/1 scale image at a distance of 200mm from subject to focal plane (4* true FL)
  
• 25mm extension on 25mm FL (focused at infinity) = 25/25 = 1/1 scale imag eat a distance of 100mm from subject to focal plane (4* true FL)
  

Temma : Good to know that, after initial focussing, no more is necessary when using a rail.

Wilt : I used the term "wide angle" because my lens is actually a 24 - 105 mm, and only suggested setting it at 50 mm as a possibility for using with extension tubes and/or reversed. Would that particular lens work at 50 mm reversed, though? Also, how can a reversed lens be manually focussed? Wouldn't it be going the wrong way? As you can tell, I have never got involved with this sort of technique and it is all very strange to me.

Trik

Trik wrote in post #18496557
Also, how can a reversed lens be manually focussed?

By moving the camera forward and backward with the rail.

I don't touch the focus ring on my reversed Minolta 50mm.

A lot of this is counterintuitive, but that's how it works.

Do you set focus at infinity then, Temma? And do you think my 24 - 105 mm, reversed and set at 50 mm, would work?

A 'reversed lens' is an ambiguously used term...it can be either

1. a lens mounted to another lens, front-to-front, rather than directly to the body
   
2. a lens mounted via an adapter which allows the front of the lens to be directly mounted to the body
   

Thanks for the explanation, Wilt, and for pointing out the disadvantage of #2.

I have thought of another drawback to a reversed lens, i.e. my Twin-Lite won't fit...

I have been window-shopping and like the look of the Fotodiox Pro Extension Tubes (as suggested by Temma) and the Manfrotto Micro Positioning Plate (only forward and back but the adjustments can be less than 1mm according to some reviews I have read). Any thoughts on those choices, please, before I go ahead?

Thanks