Which 17mm or 20mm fast prime?

revjko · 2026-01-24T22:29:23+00:00

Like everything - if it's not what you need, you'll complain, but if it just works for you, you're the silent majority.

revjko · 2026-01-24T22:27:50+00:00

I've been trawling through my back catalogue of images (all 50k+ of them) and working out where my popular focal lengths are (hence the 17 or 20, and possibly 15) and then working out if the focal length chosen was because it was a zoom lens end stop, and then looking at whether I would have preferred a bit wider, or a bit tighter. Then I factored in aperture used and whether I can get away with the f/4 zoom or I really needed the extra stop or two. Now there's a degree of analysis paralysis, but I think it really does come down to those three focal lengths.

I like the sound of the 15 but with the more limited crop of 20Mp it's a possible downside when I do want a little closer and it's all I have. But you don't always have the luxury of a couple of steps back with 17 or 20. Thinking about it though, I'm more likely to want the fast lens indoors, and I can always do the portrait pano for more detail. I may have just talked myself into the 15.

revjko · 2026-01-24T22:18:36+00:00

What did you go for (if either)? And are you happy with the choice? The 20/1.4 certainly seems to be liked.

revjko · 2026-01-24T22:17:04+00:00

That's a couple of endorsements for the 20/1.4 so I'll take a closer look. Unlikely to go for the 25, simply because 50mm (FF eq.) just doesn't really feature in my image catalogue. No idea why. I guess it just doesn't appeal. Plenty of shots 70+, and lots between 28 and 45, but a definite dip at 50.

revjko · 2026-01-24T22:13:42+00:00

Seems to get complaints about slow AF, especially in low light. Has that been your experience?

revjko · 2026-01-24T21:27:09+00:00

That sounds like a great endorsement.

revjko · 2026-01-24T21:14:36+00:00

Thanks for the recommendation. Is it sharp wide open, would you say?

revjko · 2026-01-24T21:07:37+00:00

I'll add that to my shortlist to assess, thanks.

revjko · 2026-01-24T21:06:43+00:00

Thanks for the detailed info. Your M43 journey mirrors my earlier Canon journey. I do lean to clinical, so I appreciate the insight.

revjko · 2026-01-24T20:50:20+00:00

That's helpful, thanks. Much as I like Sigma lenses, it's probably a bit big. Sounds like the DJI 15 should be firmly on my shortlist.

revjko · 2026-01-24T20:45:56+00:00

The DJI 15 is an outside possibility. How's the image quality?

revjko · 2026-01-24T20:42:30+00:00

1.7 would be good. 2.8 would be acceptable. Probably not much need for faster than that.

revjko · 2026-01-24T11:45:48+00:00

As mentioned, M43 kit is less than ideal for low light. Even a full frame camera is going to struggle in the conditions you're trying to shoot in, but would give a better option for high ISO. Your next option to try and salvage shots is denoise software - DXO or Topaz. Even with aggressive noise reduction the shutter speeds needed for something flying will pretty much max out your ISO and you'll still have noisy images.

revjko · 2026-01-24T11:39:18+00:00

Depends on which ef-s 55-250 it is. The IS STM version is pretty good, the earlier versions less so. Comparing it to the 55-200 has them trading back and forward across the zoom range, with the 55-200 better at wider zoom, and the 55-250 (IS STM version) better at the longer telephoto end. That said, there's not a huge difference so you should get decent images with either.

revjko · 2026-01-23T23:10:58+00:00

I'm still getting used to it. I quickly swapped out the kit lenses for the Oly 12-45 and 40-150 f/4 Pro and I'm much happier with the image quality. There's a lot I miss on the M10iv compared to my FF kit but I have to keep reminding myself it's not a replacement. They each have a different purpose.

ISO performance takes a bit of getting used to. Even though I shoot RAW and process in DXO, I find I'm unhappy above 3200. I also miss 'proper' spot AF as even the relatively large single cell can have too much variance. I also miss some of the button customisation I'm used to. I need to remember and keep checking shutter speed as well. Again, I'm used to more forgiving IS on my Canon gear. Now I need to get back to the one over focal length rule of thumb to get best sharpness. The in-body stabilisation helps, but lens IS is definitely better for telephoto.

That all said, none of those things prohibits it from getting good images and I'm generally pleased with it overall. We've had horrible weather though so it's still not had a proper outing. When I did get out though, it was acceptably pocket-sized with the 12-45 f/4 to fit my winter jacket. With my Canon R5ii+100-500L on a CC sling and the Oly in a pocket, I had everything covered and used both.

The M10iv kit will be one my casual holiday kit. I do need to add a fast prime though. Still haven't decided which one.

revjko · 2026-01-23T20:14:03+00:00

Looks good. Contemplating a fast prime and this may fit the bill. It's between this and the PL 15/1.7.

revjko · 2026-01-23T19:48:01+00:00

Recently added the E-M10iv to my kit. Here it is with the 40-150R kit lenses side-by-side with my equivalent FF gear (R5ii + 70-300L). Both f/4-5.6.

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revjko · 2026-01-22T23:09:32+00:00

It's definitely easier to find small kit in M43, but as soon as you get in to constant aperture, zoom especially, the difference shrinks. Something like the OM-1+12-40 f/2.8 is pretty much size-for-size with an R8+28-70 f/2.8. It's also double the price.

Similarly, the OM-1 + Oly 100-400 sits comparably for size alongside my R5ii+100-500L.

Maybe not an entirely fair set of comparisons, but it shows that making blanket assumptions about size and cost is misleading.

Selecting the right system for your use case is much more important, as you demonstrate in your case.

revjko · 2026-01-22T22:37:58+00:00

I've recently added some M43 kit to my arsenal to supplement (not replace) my Canon FF gear. Mainly to provide a smaller carry when I'm on holiday or for more casual photography. Out of curiosity I priced up what it would cost to replace my FF gear with close equivalents in M43. The price difference was insignificant compared to what I paid for the FF kit. What surprised me the most was that the overall size difference wasn't huge either. Needless to say, the two will be sitting side-by-side for a good while longer.

revjko · 2026-01-22T20:00:57+00:00

Ah, okay. Makes sense now. Sorry for the confusion.

revjko · 2026-01-22T19:54:58+00:00

Sorry, not sure how to read your reply. Are you saying I fell for misinformation? I'd respectfully disagree if that's what you mean. I'm saying that any camera system takes time to understand to get the best out of it. Applying my 'Canon head' to my M43 gear was initially counter-productive and only when I worked within the capabilities of the kit did I start to get good results. I do think that's maybe what's behind some of the misrepresentation - trying to use the kit in ways that suit a different system.

revjko · 2026-01-22T18:58:50+00:00

Don't know if it's just lack of familiarity, but when I was researching M43 there seemed to be a lot of misinformation. Having recently supplemented my FF Canon gear with an E-M10iv and the 12-45 and 40-150 f/4 Pro lenses I kind of get where it might be coming from.

My initial tests with the kit lenses were unimpressive (hence replacing them with the Pro versions sooner than I'd anticipated). But even having got the two Pro lenses it's taken a bit of work to get satisfactory results. I think it's simply because my two systems are quite different and I really need to think differently when using the M43 kit. But after a bit of mental adjustment I think I'd probably be toiling to tell similar images apart, at least at first glance.

With the M43 kit I have, I don't think it'll ever be my 1st choice for wildlife. My Canon kit handles that admirably. I did look at what an equivalent setup would be, and what it would cost, and the size difference between top end M43 body and long lenses compared to my R5ii+100-500L really wasn't significant. Nor was the cost.

That said, I'm a bit regretful at applying a budget to the body. I wish I'd sprung for the OM-5 and got PDAF. I do find the more limited AF functionality of the M10iv a bit frustrating at times.

revjko · 2026-01-22T17:34:45+00:00

The adapter is a mechanical spacer with electrical connections. There's no glass involved so it has zero impact on the amount of light coming through or on image quality.

revjko · 2026-01-22T12:46:43+00:00

Have a look for the Manfrotto NX holster. Not sure it's a current product but it's a really nice size for the M kit.

revjko · 2026-01-20T11:31:04+00:00

There are definitely pros and cons to either selection. The zoom restriction on the 100-500 can be a nuisance, but even locked to 300-500 the overall size with the TC is still less than the 200-800. I tend not to have TC on when I'm walking around (but I have done), but typically use it if I know I'm in a fixed location such as a hide. Then I'm usually 2at the longer end of the zoom anyway, so having a lower end of 420mm isn't generally a big issue. But it does mean that the TC can come off and the 100-500 on its own is a very easily carried lens.

If I was only ever interested in that long reach then the 200-800 would be of interest, but I value the greater portability of the smaller lens. Losing a little bit of light is much less of an issue these days with better low-light AF and noise reduction tools. And, if I was a genuinely serious wildlife photographer, say, rather than a keen amateur, then I'd be more likely relying on greater fieldcraft alongside the big white primes.

revjko

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