Olympus zuiko 45 1.8: is my copy sharp enough?

Started Apr 27, 2013 | Discussions thread
azazel1024 Senior Member • Posts: 1,134
Re: Olympus zuiko 45 1.8: is my copy sharp enough?

Owning both the 45mm and the 25mm, here is my experience with my copies.

I wouldn't describe the 45mm as soft at any aperature. I would however say that the 45mm sharpens further stopping down. I see no noticable improvement beyond f/3.2. That is the sharpest aperature on mine. The corners are a little weaker than the center below this, by f/3.2 the corners are very close to the center.

The center sharpens only slightly till f/2.5, beyond that I see no noticable improvement upon stopping down.

I'd consider the lens about a B+ in the center and a B- in the corners wide open. By f/3.2 it is an A- in the center and B+ in the corners on an abritary "cause I said so" scale.

The 25mm is very sharp in the center from wide open, but I WOULD call it soft in the corners. I would not call it very soft though. Mine hits "sharp" in the corners at f/2.2 (f/1.4-2 it is soft and doesn't improve much until you hit f/2.2 when it jumps greatly in corner resolution). I see maximum corner resolution at around f/3.5. It is however, sharp in the corners from f/2.2 on.

The center improves only slightly upon stopping down. I see maximum center resolution achieved by f/2.8 and it does not improve upon stopping down further.

I'd grade the 25mm as an A- in the center and a C in the corners wide open. I'd give it an A+ in the center and a B+ in the corners at f/2.8 and I might nudge that up to an A- in the corners around f/4.

It is all how you judge results as acceptable to you, but I don't find my copy of the 45mm f/1.8 anything that I'd call "soft" at any aperature center or corners. I would repeat though, it does improve some upon stopping down, it is just from an already fair high level of resolution that it does improve. The 25mm on the other hand just has outstanding center resolution from wide open and improves only a small amount upon stopping down. The corners are weak/soft wide open and don't improve much at all until f/2.2 where suddenly they go from soft to fairly sharp and once you stopped down a little further they go from fairly sharp to VERY sharp.

My 45mm probably loses out slightly to my 25mm in the center at f/1.8, but it beats the pants off my 25mm in the corners at f/1.8, f/2 and maybe even f/2.2. The 25mm pulls ahead slightly in the corners after that. Either lens is very sharp, especially so compared to a lot of other lenses when wide open, and when stopped down the story just improves.

*edit* Oh, just to expand upon my thoughts, I wouldn't hesitate to shoot with either lens for 11x14s at any aperature. Frankly, the difference in resolution between f/1.8 on the 45mm and f/4 on the 1.8 probably would be very hard to see unless I was look at 11x14s at 300DPI almost getting my nose grease on both of them. Not something I could probably tell the difference with in something so pedestrian as a couple of 8x10s at arms length. The 25mm I also probably couldn't tell the difference, except maybe the corners. That I can/could probably tell the difference in something like a couple 8x10s side by side, but it wouldn't be super profound.

Both lenses bring sufficient resolution to the table at all aperatures to make me happy and produce good pictures and prints (for me anyway). So I try not to sweat anything else. Certainly no weaknesses that make me avoid using the lenses at certain aperatures. Though I might not use the 25mm to shoot a landscape at 25mm and then print an 8x10 of a crop of one of the corners. Well, I tend not to shoot landscapes wide open no matter what.

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Many things dealing with Olympus and their OM and Pen cameras, plus my general photography and musings http://omexperience.wordpress.com/

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