NikonGear'23

Gear Talk => Lens Talk => Topic started by: Frank Fremerey on January 23, 2016, 13:49:45

Title: Experimental use of Biotar 2/25mm
Post by: Frank Fremerey on January 23, 2016, 13:49:45
If it is possible to use the Biotar 2/12,5mm as a Super-Macro I thought why not try the 2/25mm?

http://www.fotografikgalerie.de/ExtremmakrosHeliconFocus.pdf

I am currently searching for a Retroring, but I am not sure whether it must be 39mm or 40mm?

sorry, stupid me. It is more in the 50mm range (48? 49?)

I still do not know where to buy.
Title: Re: Experimental use of Biotar 2/25mm
Post by: Frank Fremerey on January 23, 2016, 13:53:04
this is how it looks like:
Title: Re: Experimental use of Biotar 2/25mm
Post by: Bjørn Rørslett on January 23, 2016, 14:08:22
39 or 40.5 mm filter threads are common, Frank. Get hold of such filter(s) and try what fits. 43 mm is also seen on older lenses.
 
As soon as you have found the correct size, making a reversal ring is a breeze by use of step rings or similar. If the intended host lens is say 52 mm, you add a 52/52 "macro coupler"to the stack of rings.

I believe 40.5-52 direct step rings exist. Not so sure about 39mm, as it is less common. For 43 mm, 43->49 is ubiquitous and 49->52 also is standard size.
Title: Re: Experimental use of Biotar 2/25mm
Post by: Frank Fremerey on January 23, 2016, 14:09:43
~50mm front diameter.
Title: Re: Experimental use of Biotar 2/25mm
Post by: Frank Fremerey on January 23, 2016, 14:11:30
39 or 40.5 mm filter threads are common, Frank. Get hold of such and try what fits. As soon as you have found the correct size, making a reversal ring is a breeze by use of step rings or similar. If the intended host lens is say 52 mm, you add a 52/52 "macro coupler"to the stack of rings. I believe 40.5-52 direct step rings exist. Not so sure about 39mm, as it is less common.

Thank you

This site got me into experimental mode. Sorry I measured wrong first time.
Title: Re: Experimental use of Biotar 2/25mm
Post by: Bjørn Rørslett on January 23, 2016, 14:11:57
Looks like 49 mm could be a better starting point.

You can commence experiments with the reversed lens by using some Gaffa tape to hold it to the BR-2. Results probably improves if you add some extension as well.
Title: Re: Experimental use of Biotar 2/25mm
Post by: Akira on January 23, 2016, 14:13:58
Yes, maybe 49mm which is also very common.  I have an old Pentax M42-to-49mm reverse mount adapter.
Title: Re: Experimental use of Biotar 2/25mm
Post by: Bjørn Rørslett on January 23, 2016, 14:17:47
Frank, you need a work table looking like this :D

Title: Re: Experimental use of Biotar 2/25mm
Post by: bjornthun on January 23, 2016, 14:22:54
Frank, you will find step rings on eBay.
Title: Re: Experimental use of Biotar 2/25mm
Post by: Frank Fremerey on January 23, 2016, 14:23:15
Bjørn. If my place looks like that my wife demands divorce!

I just bought a 49-52-stepup on ebay for 3,61 Euros incl. shipping.

extensions are existing here...

gaffa tape ... how to make a nice lens look ugly in a few seconds...
Title: Re: Experimental use of Biotar 2/25mm
Post by: bjornthun on January 23, 2016, 14:25:10
Another thing. 39mm and 43mm are quite common, since these sizes are used on rangefinder lenses and some mirrorless lenses.
Title: Re: Experimental use of Biotar 2/25mm
Post by: Bjørn Rørslett on January 23, 2016, 14:34:37
Bjørn. If my place looks like that my wife demands divorce!


You have to sort priorities :D

Besides, I suppose you have a working space or den somewhere for your own use?

The K-ring sets, photographer's equivalent to Lego bricks, are indispensable when you build experimental setups. Anyone into experimentation should have a few of these. You can pick them up for pocket money on eBay, usually almost in pristine conditions, although prices do seem to increase over time.
Title: Re: Experimental use of Biotar 2/25mm
Post by: Mike G on January 23, 2016, 14:39:55
Bjorn, do you ever pick the wrong bit up and attempt to fit it?
Title: Re: Experimental use of Biotar 2/25mm
Post by: Bjørn Rørslett on January 23, 2016, 14:46:30
Often, in fact. But never try to pressure-fit anything.

Tinkering with a lot of bits and pieces can be a Zen-like liberation of mind and in fact frequently leads to finding better solutions for the problem at hand.
Title: Re: Experimental use of Biotar 2/25mm
Post by: Frank Fremerey on January 23, 2016, 14:48:35
some silk I found...

test shots and making off ... kindoff ... ggg
Title: Re: Experimental use of Biotar 2/25mm
Post by: Bjørn Rørslett on January 23, 2016, 14:55:29
OK, so it works. Good on you. This will as a side effect show you that your sensor isn't as clean as you thought :D

By looking at your setup, it is obvious more extension would improve the final result because you improve the relationship of conjugate distances to become more "normal" seen from the perspective of the lens.

Don't stop the lens much down if at all, and be aware of sources for stray light. Illuminating the scene with a flash is usually a good starting point for nice photomacrographs. In fact, studio flashes can be ideal because they are "large" light sources.
Title: Re: Experimental use of Biotar 2/25mm
Post by: Frank Fremerey on January 23, 2016, 14:59:58
this is more like it really looks like. and I found the smaller apertures to be better for the purpose too...
Title: Re: Experimental use of Biotar 2/25mm
Post by: Bjørn Rørslett on January 23, 2016, 15:15:53
You cannot increase depth of field much by stopping down, and at these magnifications only serves to destroy image sharpness due to diffraction.
Title: Re: Experimental use of Biotar 2/25mm
Post by: Frank Fremerey on January 23, 2016, 15:24:25
my money seems to be dirtier than my camera sensor...

yes, the god of stacking has to buy a macro slider first or a micrometer holder/mover...
Title: Re: Experimental use of Biotar 2/25mm
Post by: Thomas G on January 23, 2016, 20:40:10
Frank,
that looks promising  8)
Title: Re: Experimental use of Biotar 2/25mm
Post by: Bjørn Rørslett on January 23, 2016, 21:28:39
Is this a lens originally intended for cine? Such lenses can often deliver pretty good results for photomacrography because they were designed to have high resolution over a small format. In contrast, lenses for video usage have much lower resolution and tend to perform poor for high magnification, whether they be reversed or not.

Frank: do shoot a ruler so as to be able to calculate the actual magnification. My guess is that a reversed 25 mm lens should deliver 7-8 X or more for it to be in a more appropriate conjugate relationship.
Title: Re: Experimental use of Biotar 2/25mm
Post by: Frank Fremerey on January 23, 2016, 22:05:07
Yes. Cinema. Yes. Ruler. Tomorrow.
Title: Re: Experimental use of Biotar 2/25mm
Post by: Frank Fremerey on January 24, 2016, 19:24:22
a ruler shot for Bjørn:

(note that the rectangle is 5 x 5 sqmm)
Title: Re: Experimental use of Biotar 2/25mm
Post by: Bjørn Rørslett on January 24, 2016, 19:27:31
That's only around 3.5X, assuming the entire FX frame is shown. Try to get at least 7X and the quality should be better.
Title: Re: Experimental use of Biotar 2/25mm
Post by: Frank Fremerey on January 24, 2016, 19:34:31
OK, I will get some more extension rings.
Title: Re: Experimental use of Biotar 2/25mm
Post by: Erik Lund on January 24, 2016, 21:47:11
Please note just for info that Gaffer tape is not very light proof....
Title: Re: Experimental use of Biotar 2/25mm
Post by: Frank Fremerey on January 25, 2016, 09:34:28
It is a temporary measue, Erik. The reducer ring from 52 to 49 is in the post...
Title: Re: Experimental use of Biotar 2/25mm
Post by: Erik Lund on January 25, 2016, 12:46:32
That doesn't make Gaffer tape light proof Frank  ::)
Title: Re: Experimental use of Biotar 2/25mm
Post by: Frank Fremerey on January 25, 2016, 17:47:32
No. Better. That leaves is out of the picture.
Title: Re: Experimental use of Biotar 2/25mm
Post by: Erik Lund on January 25, 2016, 20:49:06
That still doesn't make Gaffer tape light proof Frank   ::)
Title: Re: Experimental use of Biotar 2/25mm
Post by: pluton on January 25, 2016, 20:51:47
That doesn't make Gaffer tape light proof Frank  ::)
I don't know if the European terminology is different than for North America, but in the example photo that Frank posted, the construction appeared to have been fastened with Duct Tape.
Gaffer Tape is a thicker, more opaque product, though lightfastness is not in the official specs for either.
Title: Re: Experimental use of Biotar 2/25mm
Post by: Erik Lund on January 25, 2016, 21:02:33
Same same quote from wiki;
Duct tape or duck tape is cloth- or scrim-backed pressure-sensitive tape - often coated with polyethylene. There are a variety of constructions using different backings and adhesives. One variation is gaffer tape - ........
Title: Re: Experimental use of Biotar 2/25mm
Post by: Frank Fremerey on January 26, 2016, 20:12:19
Erik:

Penguins don't vomit in the Sahara desert
and sheep don't mourn your stolen property
and Frank did not know Dadaism is so popular in Denmark
or as Cato used to say "duck tape lets the sunshine in"
Title: Re: Experimental use of Biotar 2/25mm
Post by: Akira on January 26, 2016, 20:25:11
Frank, looks nice.  You would need more extension, though,,,
Title: Re: Experimental use of Biotar 2/25mm
Post by: Erik Lund on January 26, 2016, 21:23:10
Erik:

Penguins don't vomit in the Sahara desert
and sheep don't mourn your stolen property
and Frank did not know Dadaism is so popular in Denmark
or as Cato used to say "duck tape lets the sunshine in"

Why are you so hostile? I just pointed out a mere fact to warn people here on the site  ::)