step up/down rings

Photomicro · Post by **Photomicro** » Fri Feb 08, 2019 3:29 am

I am trying to find a ring so that I can fit an accessory that is 42mm screw thread (male) to a filter thread on the lens (female) of 46mm.

Many vendors seem to be very confused as to whether they consider this a 'step up' or 'step down' model, with one contradicting the other.

However, even searching I have yet to find one that goes the right way of these sizes. Even the huge multi-sets from China seem to have this due of sizes missing. Only one I found was in Australia, with postage five times the actual cost. I am in UK.

Any experiences would be welcome.

Adalbert · Post by **Adalbert** » Fri Feb 08, 2019 3:44 am

Hi Mike,
You can go via 52mm (M42->52mm == 52mm->46mm)
BR, ADi

Ichthyophthirius · Post by **Ichthyophthirius** » Fri Feb 08, 2019 4:24 am

Try this; at least it is listed correctly: https://www.bristolcameras.co.uk/p-step ... 6-42mm.htm

Photomicro · Post by **Photomicro** » Fri Feb 08, 2019 7:37 am

Ichthyophthirius wrote:Try this; at least it is listed correctly: https://www.bristolcameras.co.uk/p-step ... 6-42mm.htm

Thanks, ordered from them. At least I won't have to wait for the slow boat from...

cheers

bralex · Post by **bralex** » Fri Feb 08, 2019 9:59 am

I bought several sets of step-up and step-down rings due to the confusion - mine and the vendors - between which is which. All I can say is that they are pretty cheap and I've always got a bunch to choose from

Consider, if that particular one isn't expensive, buying both, just to cover the possibilities.

Pau · Post by **Pau** » Fri Feb 08, 2019 10:46 am

Ichthyophthirius wrote:Try this; at least it is listed correctly: https://www.bristolcameras.co.uk/p-step ... 6-42mm.htm

curiously the link doesn't work

rolsen · Post by **rolsen** » Fri Feb 08, 2019 10:49 am

Pau wrote:
Ichthyophthirius wrote:Try this; at least it is listed correctly: https://www.bristolcameras.co.uk/p-step ... 6-42mm.htm
curiously the link doesn't work

Works fine here, Firefox and Mac Mojave.

Pau · Post by **Pau** » Fri Feb 08, 2019 10:52 am

Both with Chrome and Firefox in my computer and phone shows "Not Found"

rolsen · Post by **rolsen** » Fri Feb 08, 2019 10:57 am

Pau wrote:Both with Chrome and Firefox in my computer and phone shows "Not Found"

Perhaps a DNS error then. Does the homepage work? https://www.bristolcameras.co.uk/

Pau · Post by **Pau** » Fri Feb 08, 2019 11:03 am

Yes, it does, although I can't find it searching at the site.
Just curious, I'm not interested in the adapter

rolsen · Post by **rolsen** » Fri Feb 08, 2019 11:16 am

Pau wrote:Yes, it does, although I can't find it searching at the site.
Just curious, I'm not interested in the adapter

Happens a lot for me in FM Forums.

Macro_Cosmos · Post by **Macro_Cosmos** » Sat Feb 09, 2019 3:10 am

So 42mm internal to 46mm external?

Just draw something like this, here is 877289947 hours in CAD:

In addition to that, you need to be aware of the thread pitch. M42 commonly comes in M42x1 and M42x0.75 (aka T2). The filter threads of most lenses are 0.75 pitch and the threads of most standard Chinese focusing helicoids is 1.00. While it's physically possible to twist say a M52x1 external thread into a M52x0.75 internal thread, it might cause damages to the threads. Some might not even like the idea of doing that, feels iffy.

ChrisR · Post by **ChrisR** » Sat Feb 09, 2019 7:54 am

I fear the one at Bristol Cameras will be 0.75mm.
I'd expect to have to go via 52mm.

Though T2 is 42 x 0.75mm and there are adapters to and from M42 cos I have them, but they aren't common.
If the threads are only a couple of turns they usually go together, just about!

Ichthyophthirius · Post by **Ichthyophthirius** » Sat Feb 09, 2019 11:04 am

ChrisR wrote:I fear the one at Bristol Cameras will be 0.75mm.

I assumed that's what Mike wanted to buy. 42mm for camera the usual step rings is 42x0.75.

Otherwise he would have asked for a 46 mm to 42x1 adapter.

Photomicro · Post by **Photomicro** » Fri Feb 15, 2019 1:40 pm

Thought I ought to report back. The one from Bristol cameras arrived in just a few days, and fits fine.

Since the ones from China were only 99p each, I ordered the pair as suggested to do it in 2 stages. Unsurprisingly, these have yet to arrive.

I will let you know how I get on with these.

Thanks for the helpful comments as usual. Sometimes we just need assurance that what we are thinking is sensible!