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Forum: Pentax K-1 & K-1 II 09-16-2016, 06:20 PM  
K-1 and FA43 Limited
Posted By MadMathMind
Replies: 53
Views: 15,277
I reacquired a FA50 f/1.7 and have been using that when my 77 is too long or I just want a wider shot. I've found it to my liking, although it doesn't make me swoon like FA77 does. What's interesting is that the FA77 and the FA50 have dramatically different T-stops because what's properly exposed for the FA77 (manual off camera flash settings) is often too bright for the FA50. Thinking about giving the DA55 a whirl. The focal length is starting to get too close to the 77's but I'll check it out.

What I found most displeasing about the 43, beyond its unreliability and just general disappointment in resolving power, is its distortion. I know, I've seen the barrel test images. If you get it perfectly parallel to straight lines, it's fine. What I observed was that unless you were absolutely perfect, the geometry would be very badly skewed. Huge field curvature effects. That made composing images painstaking and greatly reduced the amount of good images the lens produced for me. I don't see these issues with the FA50. At 43mm, the effects of perspective distortion shouldn't be inherently overwhelming like I was seeing.



Well, there's two of us now.
Forum: Pentax K-1 & K-1 II 09-11-2016, 07:52 PM  
K-1 and FA43 Limited
Posted By MadMathMind
Replies: 53
Views: 15,277
Here's what this thread is, in a nutshell:

OP: I hate this lens
Initial responses: No way! Mine is awesome, so yours must be bad. Post photos.

Photos posted. Then these:







After that, we get a bunch of photos from other people and a lot of "Oh, mine is awesome, so yours must be bad. Here's a web res image that looks great." None of those responses actually looked at the photos I posted and made an actual assessment of the lens/photos in question. Saying "Mine is great" means nothing because I don't know anyone's standards of great--my FA43 produces images that look fine at web res. Here's an album full of them (all 2048 by X and look great at that resolution, all taken with the K-1):
https://www.flickr.com/gp/madmathmind/EB91o5

Read the thread again. What we have in this thread past page 2 is a lot of "No, my lens is awesome and here's a photo." None of that helps me because aside from the three posts above, no one else actually evaluated my lens against theirs in any way, merely read my complaint and said "Something must be wrong." But not once in this thread do we have anyone who actually looked at the photos and said "Yes, you're right, those suck." We have quite the opposite. Just a lot of speculation that since I am unhappy with the lens, the copy must be bad, because it is impossible to be unhappy with it if it actually works (and you cite MTF scores to show me I must be irrational in not liking it).

What others think is great is seemingly not quite what I'm going for that. In that regard, the lens seems to be doing exactly what it does. But what that is is not pleasing enough to me. And like I said, it worked great on my K-5IIs. It's only the move to the K-1 that has made me unhappy with it.
Forum: Pentax K-1 & K-1 II 09-11-2016, 04:16 PM  
K-1 and FA43 Limited
Posted By MadMathMind
Replies: 53
Views: 15,277
Mine is up for sale at a below-market price in the marketplace. The consensus on this thread from those who've examined the sample images is that it seems to be within specification and I'm asking too much of it.
Forum: Pentax K-1 & K-1 II 06-28-2016, 01:19 PM  
K-1 and FA43 Limited
Posted By MadMathMind
Replies: 53
Views: 15,277
Thanks guys but photos/praise for the lens on a crop body don't help much.



This is what I thought but the two lenses feel really different to me. I think it's mostly related to curvature and distortion. While the fields of view are equivalent, distortion increases toward the edges of a lens, with more as the focal length decreases in general. You avoid a lot of the fall-off from the 31 by cropping it; with the 43 you see all of it. I've found that you need to be a lot more level and straight on with the 43 on K-1 than the 31 on APS-C.

It's definitely not as simple as "FoV = the same, shoot them the same."
Forum: Pentax K-1 & K-1 II 06-27-2016, 06:58 PM  
K-1 and FA43 Limited
Posted By MadMathMind
Replies: 53
Views: 15,277
Really? This is normal? Man...that's disappointing. I really kinda was hoping something was wrong with the lens. :/ I expected a lot more out of that 9.6 sharpness rating (but that was on a crop body). The 31 and 77 are just so, so much better...

Well, I really appreciate the feedback, guys. It helped me a lot. Thank you a dozen times! :)

I really regret selling my FA50 f/1.7 and hope that the one I just acquired is as nice as the one I sold. The DA*55 is also an option for me as well. The longer focal length may be just what I'm looking for; the 77 is my go-to but sometimes it's just too tight in cramped rooms for my model work. Kinda trying to decide what to do with the FA43 since I don't mind it as much with "stuff" if I can stop it down to f/8. Guess we'll see what happens with that FA50!
Forum: Pentax K-1 & K-1 II 06-27-2016, 06:25 PM  
K-1 and FA43 Limited
Posted By MadMathMind
Replies: 53
Views: 15,277
So, some sample photos with most of the requests satisfied. I still have to do the newspaper one. This probably isn't the best test for focus so let's discuss sharpness and detail.

For this first batch, I was about 4' (about 1m + some) away and focused on the chair's arm near the center of the photo. I didn't use a center focus point but rather one slightly off. ISO is 200. I didn't dial in any EV. Probably should have but this should work ok. I'm not really sure the best way to do 100% crops in posting so here's the images on my Google drive.

YOU CAN ZOOM TO 100% BY CLICKING THE MAGNIFYING GLASS IN THE UPPER RIGHT

Here's a link to the entire folder. You can download them as a zip. The files are named with the F-stop and the focus method for ease.
https://drive.google.com/open?id=0B9xvOLJLkOq1OFBPNEJpc2FqTkk

Now for individual files for those just wishing to sample things. I made the test fairly difficult because in normal usage, I'm trying to focus on eyes, nose, etc. Small features, in general. I put little worry in composition so that I could use focus points near the center.

f/2.8:
https://drive.google.com/open?id=0B9xvOLJLkOq1dUNCT2FYNXB0eU0
f/3.5
https://drive.google.com/open?id=0B9xvOLJLkOq1a1V1WkJNRUFOcFU
f/4.5
https://drive.google.com/open?id=0B9xvOLJLkOq1UTEwZzFnMGNRYWc

There's not a lot of sharpness variation between these photos. They all look about the same. Focus doesn't *seem* to be off, at least not in any measurable way. At f/4.5, DOF should kick in a bit and a slight miss still should render the arm chair nice and sharp. That's not what we see. It's just flat. No contrast and there's no detail.

Then I switched to Live View. Focus point is set to the chair arm again. Roughly the same distance, perhaps a bit closer.

f/2.8
https://drive.google.com/open?id=0B9xvOLJLkOq1aHlONGtTRTRIRVk
f/3.5
https://drive.google.com/open?id=0B9xvOLJLkOq1TGRTTVJRRTc5NVE
f/4.5
https://drive.google.com/open?id=0B9xvOLJLkOq1Nm9KYzJzcXRYR1k


Then I switched to MF zoomed into the chair's arm. It outlined the whole chair arm in white so it should be focused correctly.

f/2.8
https://drive.google.com/open?id=0B9xvOLJLkOq1eE5WX3EyUVJFMkU
f/3.5
https://drive.google.com/open?id=0B9xvOLJLkOq1NnBYQjcyZEZWYjQ
f/4.0 (whoops)
https://drive.google.com/open?id=0B9xvOLJLkOq1RmlOZUJaWlRmdmc


Then I backed up to about 10' or so (~3m). I focused on the left arm of the chair. These were all done with PDAF.

f/2.8
https://drive.google.com/open?id=0B9xvOLJLkOq1S1lJQXVHR3hRRW8
f/3.5
https://drive.google.com/open?id=0B9xvOLJLkOq1UHhYWmM5SkY1U2M
f/4.5
https://drive.google.com/open?id=0B9xvOLJLkOq1UVhmQWFyS3RxOG8

What we see is that there's a front focus and none of these is terribly sharp. Detail is fairly flat.


Now for fun, let's see what the FA77 does at the same distances (within a few inches) and the same focus features. I again stayed away from center focus points. Same points of focus as before. Here's the folder:
https://drive.google.com/open?id=0B9xvOLJLkOq1MEJyQjR6T3FtT3c

And individual files.

f/2.8 (close)
https://drive.google.com/open?id=0B9xvOLJLkOq1ZS1XSVVScVoxb28
f/3.5 (close)
https://drive.google.com/open?id=0B9xvOLJLkOq1S2ZkYnA4OGNjTjg
f/4.5 (close)
https://drive.google.com/open?id=0B9xvOLJLkOq1MGF6OC1RMzZMZGc

f/2.8 (far)
https://drive.google.com/open?id=0B9xvOLJLkOq1ZUhiY3NhclRkQ1k
f/3.5 (far)
https://drive.google.com/open?id=0B9xvOLJLkOq1NFV3Sldoc1hsUGs
f/4.5 (far)
https://drive.google.com/open?id=0B9xvOLJLkOq1U19oZkp3X3dxcGcWe

We see some issue with front focus a bit--frankly, this test is probably unfair for any lens as the point of focus is incredibly difficult--as well but what's in focus is incredibly sharp. There's no contest between the two lenses. The FA77 is heads and shoulders above. Zooming in to 100% reveals sharp lines and grains of paint and metal. The FOV is tighter for the FA77 but at 10', the FA77 resolves the detail better than the FA43 does at 4'.

My FA77 is calibrated and the FA43 is not. I had calibrated it for close focus and found it to miss so badly at distance that I set it back to zero. I've been unable to figure out how to make it do both well. Either it's good close or good far but not both.

---------- Post added 06-27-16 at 07:30 PM ----------

The test I didn't do was LV when near the borders of the LV AF area. The FA43 does really bad there. The FA77 is much, much better and reliably hits eyes as I desire.
Forum: Pentax K-1 & K-1 II 06-27-2016, 03:38 PM  
K-1 and FA43 Limited
Posted By MadMathMind
Replies: 53
Views: 15,277
I wrote a rather scathing review of the FA43 based on my experience with it on the K-1. I acquired it after the announcement of the camera and used it only for a short time on my K-5IIs. The huge majority of my experience with the lens is on the K1. Here's my review:

SMC Pentax-FA 43mm F1.9 Limited Reviews - FA Prime Lenses - Pentax Lens Reviews & Lens Database

@bassek PMed me about the review and asked for a bit more clarification. I incorporated some of my response into an edit of the review. I will admit that I was probably more harsh than I needed to be. I'm really, really frustrated with the lens. It can produce some nice results and it looks great on the LCD screen but....man.

I can't rule out the possibility my 43 has issues. I acquired it secondhand so it's not like I can send it back. I've not heard it being subject to copy variation much but it's nonetheless possible. As for my K-1...well, with the FA77, it's insane. I can't believe the detail it produces. The FA31 is awesome. DFA100 is stellar too. Definitely has something to do with the FA43 itself or the pairing with the body. I know others have had complaints as well, although I've been a bit louder about it.

I only briefly used the lens with my K-5IIs. I suppose I could pull that out and see how it does. I was impressed with the 43 the few times I used it on that crop body. That's where my excitement came from. But now, I couldn't be more disappointed. I just reacquired an FA50 f/1.7 that I had sold because I had anticipated using the FA43 a lot. But beyond its unreliability, I've not found the focal length to my liking either.

So...anyone else out there just finding the FA43 not up to snuff?
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