Some potential problems to be aware of when using larger filters with step-up rings:
- On most lenses You will not be able to use the lens hood with larger filter attached. Without hood there's potentially more stray light entering the glass and causing flare. Not a major issue with polarizer, because hood blocks the filter rotation and you need to remove hood anyway;
I agree that this is an issue.
When using a polarizer, I remove the hood to adjust and then replace it before taking the shot. It's a minor nuisance, but I prefer it to flare. And the time a pol filter is most useful is when there is a strong directional light from the side, which is one of the times when you most need a hood.
If a step up ring is involved, an option to consider is fitting a hood that screws onto the front of the filter. For various reasons, that is likely to be less than perfect (the geometry of the hood, whether round, rectangular or petal, is unlikely to be optimal for whatever lens you're using), but better than no hood at all...
- Filter on step-up ring will be further away from front element, which might affect the flare;
It might reduce flare slightly because of the geometry, but I think then effect will be minimal in most or all cases, and I can't say I've ever noticed any.
- Most of the cheap step-up rings are relatively poorly machined and typically made of aluminium. That increases the risk of jamming. You are probably better off buying more expensive "premium" rings with tighter machining tolerances and made of brass;
While brass step rings are certainly better (though heavier...) I've found that using a very light touch - both when mounting and removing rings - greatly reduces jamming. The issue seems to be in part that any pressure causes light alloy rings to distort, which prevents them screwing/unscrewing smoothly. Brass, being less flexible than cheaper alloys, is less prone to this issue.
- They add a bit of annoyance if you want to use a single filter on multiple lenses with different filter thread sizes simultaneously.
Yes. It's also a PIA to have to pull the filter off and transfer it to a different lens during a lens swap.
For all the above reasons, I have acquired and frequently end up carrying five pol filters (49, 67, 72, 77, 82) - which reduces some of the pain points, but adds others of its own (including the $$ tied up in having five decent filters in my kit, not to mention the added bulk).
A middle ground is probably best - ie get filters to fit the lenses you'll most often need them on, and step rings for others. If you factor in extra hoods to fit the filters, you may not save anything on bulk, but it will be a cheaper solution (i.e. cheaper than a full suite of pro quality filters).
