M52 Helicoids, how do you use them?

jjphoto · Post by **jjphoto** » Fri May 23, 2014 3:17 am

What fits into the front of an M52x1 Helicoid (such as the examples linked to below)?

http://www.ebay.com.au/itm/Extension-Tu ... a22&_uhb=1
http://www.ebay.com.au/sch/i.html?_odkw ... _sacat=625
http://www.rainbowimaging.biz/shop/prod ... roduct=366

There do not seem to be any M52x1 adapters on the market which thread into the helicoid itself.

The only readily available 52mm adapters are 52x0.75 which are for filters or lens threads and these are of no use on an M52x1 helicoid. Any advice would be appreciated as I'm confused by the abundance of M52 helicoids but the lack of anything to mount into them!

johan · Post by **johan** » Fri May 23, 2014 3:21 am

The M42 end would attach via adapter into cam, and the 52 end is for reversed 52mm lenses. 52mm is quite common, isn't it the standard Canon and Nikon size?

jjphoto · Post by **jjphoto** » Fri May 23, 2014 3:39 am

johan wrote:... and the m52 end is for reversed M52 lenses. M52 quite common, isn't it the standard Canon and Nikon size?

I'm quite familiar with M42 helicoids and adapting them to cameras as I have a couple of them. However, I don't have any M52 helicoids to confirm the M52 thread itself which I believe to be M52x1 (just like M42x1 in M42 helicoids). The 52mm reversing adapters you refer to are M52x0.75 and do not, to the best of my knowledge, fit into M52 helicoids. Maybe some one who has an M52 helicoid can confirm the thread pitch although I've read one forum post confirming it is M52x1 (not M52x0.75). Unfortunately the various sellers of these M52 helicoids do not specify the M52 pitch in their advertising.

johan · Post by **johan** » Fri May 23, 2014 4:32 am

jjphoto wrote:The 52mm reversing adapters you refer to are M52x0.75 and do not ...

Just to clarify, no, I'm not actually referring to a 52mm reverse adapter. I was referring to this eq train:

CAM => (m) Mount - M42 (f) => (m, M42) Helicoid (f, 52) => (m) 52-52 male to male (m) => (f) Reverse lens with 52mm filter thread

I must admit I don't know what size pitch these have. The 3 M42 helicoids I have that look the same (also eBay bought) all have M42 male and female. My hunch would have to be on .75mm judging from this but asking the seller to screw in a standard 52mm UV filter to check might not be such an awful idea.

jjphoto · Post by **jjphoto** » Fri May 23, 2014 4:49 am

johan wrote:... => (m) 52-52 male to male (m) => (f) Reverse lens with 52mm filter thread...

Do you mean this kind of thing?

http://www.ebay.com.au/itm/52-52-double ... 4172144d9a

johan · Post by **johan** » Fri May 23, 2014 4:59 am

Yeah - I use 49-49 male-male a lot, my Pentax stuff all has a 49mm filter ring

jjphoto · Post by **jjphoto** » Fri May 23, 2014 5:38 am

Hopefully the threads in the M52 helicoids are 0.75 to match the adapters you refer to.

johan · Post by **johan** » Fri May 23, 2014 6:49 am

Hope so!!! (In truth would surely be odd if not). But might be worth asking him/her to screw in 52mm uv filter to check

Just to clarify, do I have this right:

M42: 42mm thread with 1mm pitch
T42: 42mm thread with .75mm pitch
Most lens filter threads are actually .75mm pitch. ie your average 50mm f/1.7 might have a 52mm filter thread and that would be .75mm pitch

???

jjphoto · Post by **jjphoto** » Fri May 23, 2014 3:09 pm

johan wrote:Hope so!!! (In truth would surely be odd if not). But might be worth asking him/her to screw in 52mm uv filter to check...

I've sent messages to several sellers asking to clarify. I'll eventually buy one anyway, so I'll see for myself, but just trying to do some research first.

johan wrote:...Just to clarify, do I have this right:

M42: 42mm thread with 1mm pitch
T42: 42mm thread with .75mm pitch
Most lens filter threads are actually .75mm pitch. ie your average 50mm f/1.7 might have a 52mm filter thread and that would be .75mm pitch

???

Yeah, that's correct.