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reversing lens on lens for macro - suggestions wanted
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PostPosted: Fri Dec 30, 2011 2:18 pm    Post subject: Reply with quote
Pardon my ignorance, but what it the benefit of using two lenses together, front to front, over say extension tubes and reverser ring?


PostPosted: Fri Dec 30, 2011 2:53 pm    Post subject: Reply with quote
kds315* wrote:
I talk about those: http://www.macrolenses.de/ml_detail.php?ObjektiveNr=69
not enlarger lenses (that Tomioka also made).


There was a 12.5mm Photar from Leitz, I believe. I don't see that in your table.

http://www.bhphotovideo.com/c/product/29526-REG/Leica_14440_12_5mm_f_2_4_Photar_Lens.html

And here they are for sale:

http://www.jacobsdigital.co.uk/p-44983-jacobs-digital-leica-125-mm-f24-photar.aspx


PostPosted: Fri Dec 30, 2011 3:18 pm    Post subject: Reply with quote
WolverineX wrote:
i mean, that for my macro needs coupling ring is just enough and my funds will go for a new PEN camera that's about to be announced


me too, I'm waiting for a new Pen to replace my E-p1 Wink


PostPosted: Fri Dec 30, 2011 5:22 pm    Post subject: Reply with quote
Mos6502 wrote:
Pardon my ignorance, but what it the benefit of using two lenses together, front to front, over say extension tubes and reverser ring?

1: Knowing the precise magnification. With both lenses focused to infinity, magnification is the ratio of primary to secondary. Reverse-stacking a 35mm onto a 105mm gives (pretty) precisely 3:1.

2: Compactness. Stacking a 24mm onto a 105mm tele is shorter than reversing that 24 onto 130mm of extension. My SuperTak 105/2.8 is 60mm deep. That makes the combo 70mm shorter.

3: Less gear to haul around. Assuming both the camera-mounted primary tele and the reverse-stacked secondary shorter lens are normally in your kit, you needn't also carry bellows and tubes.

4: Related to #3 -- Improvisation. If you have the primary and secondary on hand, and no other hardware, they can be joined with gaffer's tape. No extra gear is necessary! (Avoid electrical tape.)

There is no benefit with light transmission. Both methods eat light. To avoid light loss, use a high-dioptre closeup achromat on a longish lens. By some calculations, such adapters actually INCREASE the available light. If you must reverse-stack, be sure to leave the primary's iris wide-open, and control the explsure with the secondary's aperture.


PostPosted: Fri Dec 30, 2011 6:34 pm    Post subject: Reply with quote
Because of the asymmetry of fast normal lenses, reversing them improves their performance over using them in the normal orientation. This still, though, does not bring their performance up to that of special macro lenses. The greater the magnification, the greater the difference in the quality of results.


PostPosted: Fri Dec 30, 2011 7:42 pm    Post subject: Reply with quote
Nordentro wrote:
WolverineX wrote:
i mean, that for my macro needs coupling ring is just enough and my funds will go for a new PEN camera that's about to be announced


me too, I'm waiting for a new Pen to replace my E-p1 Wink


according to rumors it should be announced in couple of weeks, be weathersealed and have integrated viewfinder, and be better than e-p3


PostPosted: Fri Dec 30, 2011 7:44 pm    Post subject: Reply with quote
RioRico wrote:
If you must reverse-stack, be sure to leave the primary's iris wide-open, and control the explsure with the secondary's aperture.


good tip, thanx Smile


PostPosted: Fri Dec 30, 2011 10:56 pm    Post subject: Reply with quote
kds315* wrote:
Get one of the TOMINON special macro bellows lenses, there come in 17/35/50/75/105/135mm focal length and can be had for a song. Need a M40-M42 (or M39) ring, available on ebay. That sets you back about $50. Data is on my macrolenses.de site.


I've seen them described as repro and enlarging lenses. Why do you call them macro lenses specifically? Where they intended for that purpose or just as repro lenses for the Polaroid?

JJ


PostPosted: Sat Dec 31, 2011 11:18 pm    Post subject: Reply with quote
jjphoto wrote:
kds315* wrote:
Get one of the TOMINON special macro bellows lenses,

I've seen them described as repro and enlarging lenses. Why do you call them macro lenses specifically?

IMHO anything that's edge-to-edge flatfield-sharp close-up can be considered a macro lens.
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