Wich 35/ f? To buy, fun factor needed.

RioRico · 09-13-2011, 02:29 PM

Nice inside-the-tent shot, repaap. What structure *is* that?

OK, sharp 35's, sure -- but how about a FAST 35? Real cheap too, and no need for any deadly-boring lens-design classes. Here's how:

Get three +10 dioptre closeup lenses, 49mm diameter; a 42-49mm step ring; and any M42-PK adapter, like a cheap safe wide-flanged one. Screwed together, the lenses form a 33mm objective. The inner diameter of the rings is 39mm, so the product is f/0.85. Yes, a 33/0.85 lens for about US$40! But the closeup dioptres aren't corrected, so images are a bit soft and aberrant, to say the least.

For something a little better, replace one of the closeup dioptres with a Raynox DCR-250 (which is optically corrected), and use a 42-41mm step ring. Screw the two remaining closeup dioptres onto the Raynox, which is +8dpt. 8+10+10dpt= 28dpt or 35.7mm. The inner diameter of the Raynox is 37mm, so the product is f/1. Yes, a 35/1 lens! Huzzah! Break out the champagne! Post it on Flickr!

Downsides: Extremely close focus only, and extremely soft images. But the damn fastest 35 you'll ever own! Be the first on your block!

repaap · 09-13-2011, 10:18 PM

Riorico, that sounds just great. But it might be little a bit too fast for me and it is over the top. But who needs infinity control and that sharpness thing is just overated anyway...let's say I think about it. If those close up rings would be pentax branded it could be some sort of new REALLY limited lens. Now without '*', BUT with "limited" sing allover it, so definetly something to ponder.

Back to reality, that 'tent' was a artpeace called - colorscape -. It was nice.

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09-13-2011, 02:29 PM	#46
RioRico Veteran Member Join Date: Jun 2008 Location: Limbo, California Posts: 11,263	Nice inside-the-tent shot, repaap. What structure is that? OK, sharp 35's, sure -- but how about a FAST 35? Real cheap too, and no need for any deadly-boring lens-design classes. Here's how: Get three +10 dioptre closeup lenses, 49mm diameter; a 42-49mm step ring; and any M42-PK adapter, like a cheap safe wide-flanged one. Screwed together, the lenses form a 33mm objective. The inner diameter of the rings is 39mm, so the product is f/0.85. Yes, a 33/0.85 lens for about US$40! But the closeup dioptres aren't corrected, so images are a bit soft and aberrant, to say the least. For something a little better, replace one of the closeup dioptres with a Raynox DCR-250 (which is optically corrected), and use a 42-41mm step ring. Screw the two remaining closeup dioptres onto the Raynox, which is +8dpt. 8+10+10dpt= 28dpt or 35.7mm. The inner diameter of the Raynox is 37mm, so the product is f/1. Yes, a 35/1 lens! Huzzah! Break out the champagne! Post it on Flickr! Downsides: Extremely close focus only, and extremely soft images. But the damn fastest 35 you'll ever own! Be the first on your block!

09-13-2011, 10:18 PM	#47
repaap Pentaxian Join Date: Oct 2010 Photos: Gallery \| Albums Posts: 6,242 Original Poster	Riorico, that sounds just great. But it might be little a bit too fast for me and it is over the top. But who needs infinity control and that sharpness thing is just overated anyway...let's say I think about it. If those close up rings would be pentax branded it could be some sort of new REALLY limited lens. Now without '*', BUT with "limited" sing allover it, so definetly something to ponder. Back to reality, that 'tent' was a artpeace called - colorscape -. It was nice.