It should allow you to mount a 52mm filter on a lens with a 5mm filter thread, that is what it is designed to do, and that would cause vignetting. Of course I have probably got that wrong, never having used such things. This might be of interest https://www.bhphotovideo.com/explora/photography/hands-review/wisdom-step-and-step-down-rings Whilst many people will swear by their stepping rings, the fact is that the cost of a high quality stepping ring may well be nearly that of a smaller/larger filter. In the world of professional audio systems "thread adaptors" are used to match microphone clips to stands but in that field vignetting isn't an issue.
It's only a step down if the larger thread is male and the smaller thread is female. If so: you screw the adapter into your lens and whatever you want to mount (such as a close up lens) into the adapter. If the larger thread is female and the smaller thread is male then it's a step up adapter.
If the primary lens has a focal length of 50mm or longer then I doubt it would be a problem - most lenses have a rebate wider than 3mm inside the filter mount so that area has to be outside the optical cone.
It varies hugely with the lens. Many older lenses were designed to use the same filter size across the range. In film days Pentax used 49mm filters for their standard 28,35, 50, & 135 lenses, I gather Canon standardized on 52mm. Many of these lenses have no need of such a wide filter and would work just fine with one a few sizes smaller. I believe there is still a fair bit of this going on, as my Olympus 17mm/2.8 prime for MFT takes a 37mm fliter by default, but when I've used 25mm filters on it there's been no issue with vignetting! Other lenses are much less forgiving
Agreed! We have two Nikon AF 50mm lenses one f1.8 and the other f1.4 both take 52mm filters, the f1.8 could happily use a smaller filter the f1.4 couldn't. The OM system Lens manual made a virtue of the fact that at each focal length one lens accepted a 49mm filter (I think it was 49) and was of a slower maximum aperture, the faster lens had a bigger filter thread. Personally, if I didn't already have filters in the sizes I need, I would probably get the biggest filter I might need, say 62mm and then the appropriate rings to use it on smaller lenses. However, if you have more than one body, and thus can use more than one lens at a time, you may need a filter on each lens and at that point having one filter and stepping rings falls down completely.
Stepping rings are very cheap, and I have a few step UP ones because I have purchased large ND grad and polarising filters to fit my Sigma 10-20, and also want use these filters on lenses with smaller filter threads. It's much cheaper to buy one filter and a few cheap step up rings than to but a variety of filters to fit different lenses. Also, I only need one folding rubber lens hood that has the same filter thread as my filters, because with my step up rings I can also use it on any lens. The only use I can think of for a step DOWN ring is to allow the use a filter or closeup lens slightly smaller than the filter thread on your lens, and then only for lenses of 50 mm or longer (on full frame) so that vignetting isn't a problem. For example, a 55 mm filer on a lens with a 58 mm filter thread.
If, like me, you regularly use two camera bodies you need separate filters for each lens you have mounted. Fortunately I rarely use filters.
Is my wife aware of the possibility of my being right? My comment was badly worded, I should have said "every lens you have mounted on a camera".
I don't see how that helps. Many of my lenses have never had a filter fitted while I've had them, despite the fact I shoot a lot of infrared so need to use filters more than most photographers.
Allow me to explain, many people look at the price of, for example, a 62 mm circular polariser and decide that they will use a 58mm example with a stepper ring. This filter will serve both a lens with a 58mm filter thread and one with a 62mm filter thread. If one is using two bodies, with both lenses fitted the one filter cannot be on both lenses at the same time. I am rather making the assumption that these are lenses of similar focal length such as 50mm and 85mm. A situation in which having both lenses fitted with such a filter may be appropriate. Hence my suggestion that the use of a stepping ring may not be practical if one regularly carries two cameras. Like you I very rarely use filters but I do have circular polarisers and I know how expensive they are.
I didn't say I rarely use filters, I actually use them extensively. I just don't use protective filters - moving filters between lenses is common for me - especially when changing lenses on my IR cameras. My MFT IR camera normally lives with a 17mm/2.8 lens (which takes 37mm filters) but I usually leave a stepping ring to 52mm & a 25A filter on it. If I switch to one of my standard native zooms they take 52mm filters so it simplifies matters. Much easier than finding another 25A filter in the right size. If I want a 720nm filter, or 890nm filter or one of the blue+ IR filters... I have all of these in 52mm so can fit on any of the most used lenses. If I want something more exotic like a U330, or BG3 I've only got those in 37mm (or stepped up to 37mm) so the zooms are out. CPLs are dirt cheap compared to some of these in lager sizes - getting them with a thread at all involves custom manufacture. In most cases leaving the filter I'd use for IR on the lens makes it totally useless for normal visual shooting.
Sorry, of course you didn't I was just being lazy and not checking before I posted. However, the point remains, stepping rings are probably great if you swap filters between lenses but, if you are using two lenses, on different cameras, at the same time, two filters may be required.
