Originally posted by Conqueror That doesn't mean the 20-40mm isn't good... its just I needed to experience the 31mm
Yes, you
do need to experience it. For me it was the hardest lens to get what I wanted out of it. But at times it was great. IQ is very good wide open - that alone makes it worth trying.
Its defining characteristic is that it's nearly impossible to tell precisely when (at what depth) objects go from in-focus to Out-Of-Focus. This can be either good or bad. It's good in that this lens' smooth transitions to OOF and smooth OOF rendering makes it almost impossible to get a harsh background. The downside is that you can't make in-focus images in the foreground stand out (appear isolated) as obviously as on most any other fast lens. If the background is far away it's obvious, of course, but not so much if the background is close or other objects are adjacent to the subject. This can require re-thinking your photography, unless mediocrity satisfies you. You can't just pick a subject and focus on it - you'll have to think about how the rest of the scene will affect the shot when this lens' unique rendering is applied to it.
Note that I usually shoot closer to wide-open. Most of my shots were between f/1.8 and f/4. It's a high quality lens that can do well stopped down to f/8, f/11, or beyond - see the MTF charts:
Pentax SMC FA 31mm f/1.8 AL Limited - Lab Test / Review - Analysis I neglected this part of the lens' ability, and probably should have paid more attention to it. But
many lenses can do well at f/8 or f/11. The FA31 is strong throughout the aperture range, which makes it versatile. Nevertheless, I think the main point of this lens is its wide-aperture characteristics. Possibly also its more "film like," not "digitally sharp" rendering (and even within film-era lenses it's very unique).
Watch out for these characteristics and potential pitfalls:
- I took some photos with it at a wedding photography workshop at Legion of Honor, at a spot overlooking the Golden Gate Bridge. Obviously the background was far away. My daughter said it looked "phony, as if I'd cut out the bride and pasted her against the background in Photoshop." How ironic that one of the world's best lenses has a natural character that made her stand out so well that it looked "phony!"
- Beware of front-focus. That's about the worst thing that can happen with this lens, and my copy had it. Either send it in for adjustment, or make sure the camera's AF adjust compensates properly. You see, with front-focus, in a typical shot
everything ends up out of focus. But with this lens, rather than looking clearly OOF, everyone just looks slightly blurry and unsatisfying (e.g. with a family shot of a small group). You may not realize what's going on a first, and simply wonder why the lens is under-performing!
- Sharpness - at least the way I think about it - isn't really this lens' defining characteristic. But that doesn't bother me per se - I value other characteristics more highly anyway. Nevertheless, I found it tricky to make it produce what I wanted from it.
- Probably most importantly of all - Don't give up and take it off the camera! It can take good portraits - sometimes full-body portraits. What looks mediocre or uninteresting on the back of the camera may look quite good when you load it up on your computer. This problem is compounded by the fact that I've seen
more un-interesting photos posted online from this lens than any other
genuinely high-quality lens I can think of. It can take some work,
and you can't even tell if you've been successful until later! So the potential for failure is real. It's not like a 135mm lens, which magically makes you look (and feel) like a good photographer simply because you can focus and compose decently while using a wide aperture. It's unlike any lens I've ever used. Sometimes I think even my FA Soft lenses are less tricky.
On the other hand, I got some fantastic shots with it indoors, like the one where my brother's kids were climbing all over him. This lens really came through. It ended up on his Christmas card.
It also seems very nice for video.
You need to get your hands on one to see for yourself. I finally sold mine, but I'm keeping my FA*24. I like the wider FL, and I just wasn't using the FA31 much. I might not have sold the FA31 if it were rare, but that's hardly the case! It really is amazing in some unique ways. Since it has good resale value,
get one. You can even change your mind, sell it, and buy another some day!
Last edited by DSims; 01-31-2015 at 03:54 PM.