[chesebert]

I only use one focus point because I really want the center, or, what I am focusing on, the subject in the center of the photo to be sharp. If there's a little softness at the edge I'm okay with that. I really do want WR because sometimes I have to pass up on some shots due to the rain.

I am think I am pretty much stuck, with not many choices in the WR area. Instead of moaning, I am going to go out and take some pictures.

[normhead]

I am going to go out and take some pictures.

Good choice. That's just the way it is with this lens. It's also a lens designed to take 3d pictures IMHO. I have no idea how the tech guys justify using 2D tests on lenses used for the most part in a 3D world. I remember one poster complaining about the part where you can't focus the edges and middle at the same time in MTF tests. Well think about it. Your subject is in the foreground, your background is behind, most of the time. Wouldn't it be interesting to design a lens to promote both subject in focus and maximizing the focus on the background behind it. Such a lens would suck on flat plane tests, but it might give you better pictures in the 3d world most of us shoot in. Flat plane MTF is the lazy man's way of evaluating lenses. And the sad thing is, the people who do it will put out lens ratings based on a 2D world that they, as designers know better than anyone else, mean little in a 3D world. Those people who should know better for whatever reason, create a skewed version of reality, that they acknowledge is flawed, and then go right on spitting out useless data anyway.

If they had any credibility at all, they'd come right out and say "you can't take a good picture with this lens", instead of hiding behind a flat world. But they won't do that, because they'd be proved wrong over and over again. I have great pictures taken with the kit lens, or my old Optio W10. If my experience with thte 18-135 taught me anything it's for the most part the guys who design the lenses I like, weren't designing to meet flat plane MTF criteria. And the reason for that is, flat plane MTF numbers do not predict what lenses produce the best images, day in day out.

[joe.penn]

No one cares aesthetically what is at the extreme edges of a photograph

Well, it is kind of important, and extremely important if you are shooting large group pictures...

[chesebert]

Good choice. That's just the way it is with this lens. It's also a lens designed to take 3d pictures IMHO. I have no idea how the tech guys justify using 2D tests on lenses used for the most part in a 3D world. I remember one poster complaining about the part where you can't focus the edges and middle at the same time in MTF tests. Well think about it. Your subject is in the foreground, your background is behind, most of the time. Wouldn't it be interesting to design a lens to promote both subject in focus and maximizing the focus on the background behind it. Such a lens would suck on flat plane tests, but it might give you better pictures in the 3d world most of us shoot in. Flat plane MTF is the lazy man's way of evaluating lenses. And the sad thing is, the people who do it will put out lens ratings based on a 2D world that they, as designers know better than anyone else, mean little in a 3D world. Those people who should know better for whatever reason, create a skewed version of reality, that they acknowledge is flawed, and then go right on spitting out useless data anyway.

If they had any credibility at all, they'd come right out and say "you can't take a good picture with this lens", instead of hiding behind a flat world. But they won't do that, because they'd be proved wrong over and over again. I have great pictures taken with the kit lens, or my old Optio W10. If my experience with thte 18-135 taught me anything it's for the most part the guys who design the lenses I like, weren't designing to meet flat plane MTF criteria. And the reason for that is, flat plane MTF numbers do not predict what lenses produce the best images, day in day out.

All good points, except my FA limited are sharp on the 2D test and even better in the 3D world. Granted, they are priced differently and have different uses.

[normhead]

Well, it is kind of important, and extremely important if you are shooting large group pictures...

And you've seen a lens that is so bad that the edges in a group picture were un-acceptable? You've seen portraits where extreme sharpness was necessary, at all? What? someone at the edge of the frame wanted to use the picture to check for zits? What happened to the good old days when our portrait lenses were bought to be soft, but meant to produce a pleasant, appealing softness? Sharpness wasn't even a consideration in a portrait lens. Rendition of subject was.

[audiobomber]

I have seen it compared to the "other" super zoom that Pentax had (the DA 18-250) and it actually stacks up pretty well. Obviously not as much range, but overall similar IQ. A super zoom is a super zoom -- it will have more areas of weakness than lenses costing more that have smaller zoom range. I also think there is quite a bit of variation in copies -- some pretty decent and others not so good.

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/151855-18-135-vs-16-45-15mm.html. (looks like he took down the photos of the 18-250 versus 18-135 shots).

Here's a brick wall shot with the DA 18-135 vs DA 18-250, tripod, 2s lockup.
https://picasaweb.google.com/bonhommed/18135Vs18250?authkey=Gv1sRgCNzC5b_4_qXRqQE#

Here it vs the DA 55-300mm:
https://picasaweb.google.com/bonhommed/18135Vs55300?authkey=Gv1sRgCO7y5LGM3-rKEA#

My copy beats my 18-250 and my DAL 18-55 in every way (colour & contrast, CA, PF, sharpness across the frame, flare, bokeh). It shows more vignetting than my other standard zooms. It is not as sharp as my 16-45 or 55-300. I'm satisfied with the IQ of the 18-135. My kit has become 18-135 + primes. My other zooms are languishing. I am over the moon with the mechanics of the lens; build quality, WR, size, rounded blades, quick & silent AF. When I first got the lens, it was unusable on my K-x. I had to set it for +10 to AF on my K20D. I sent it back for repair and it's fine now on either camera with no adjustment.

135mm, f5.6


135, wide open again:


135mm f8

[VoiceOfReason]

I am think I am pretty much stuck, with not many choices in the WR area. Instead of moaning, I am going to go out and take some pictures.

That's always the best thing to do! It's what we all have our lenses for. If the picture is pleasing who cares about the mechanics of the lens? Besides, you can smile at the canikon people running for cover in a little drizzle!

[normhead]

except my FA limited are sharp on the 2D test and even better in the 3D

My 21 Ltd is rated really poorly MTF and produces amazing shots. There is nothing to say that a lens that does good on 2D tests won't produce great images. But there's also evidence that some lenses that don't do well on MTF test produce great images as well. SO what do those things really mean? To me, the reputation on the forum is worth more than flat plane MTF tests. Based on MTF numbers I thought my DA*60-250 would out perform my Tamron 90 macro. Nothing could be further from the truth. On all of my bodies from (K20D - K-x , K-5) that lens is magic. I would have thought there might be a small difference, and it's really not a matter of sharpness at all. There's stuff way more than sharpness going on, that makes those 21Ltd and Tamron 90 macro images standouts. Both of those lenses were bought on the recommendation of forum members. On MTF alone, I wouldn't have purchased either.

In fact I'd go so far as to say, every lens made today has acceptable sharpness... the difference between good (beacuse I don't know of any truly bad lenses still in production) and great lenses is how they render out of focus areas, and as far as I know, there's no objective measurement for that.

[Clavius]

My 21 Ltd is rated really poorly MTF and produces amazing shots. There is nothing to say that a lens that does good on 2D tests won't produce great images. But there's also evidence that some lenses that don't do well on MTF test produce great images as well. SO what do those things really mean? To me, the reputation on the forum is worth more than flat plane MTF tests. Based on MTF numbers I thought my DA*60-250 would out perform my Tamron 90 macro. Nothing could be further from the truth. On all of my bodies from (K20D - K-x , K-5) that lens is magic. I would have thought there might be a small difference, and it's really not a matter of sharpness at all. There's stuff way more than sharpness going on, that makes those 21Ltd and Tamron 90 macro images standouts. Both of those lenses were bought on the recommendation of forum members. On MTF alone, I wouldn't have purchased either.

Same with the DA35ltd, according to the MTF charts at Photozone, it's supposed to be not all that sharp. While in practice, it turns out to be super-sharp.

I am think I am pretty much stuck, with not many choices in the WR area. Instead of moaning, I am going to go out and take some pictures.

That's always the best thing to do.

I see you have some very excellent primes in your lineup. I have some too, but I would certainly NOT submit them to rain, or moist, or dust, etc. And, of course, when I know I won't have the time to switch primes all the time. What I want to say is, for a powered WR superzoom, the 18-135 is pretty good. The corner softness is inherent to the large zoomrange. I don't even know why people worry that much about the corners, 9 times out of 10 that's where the bokeh is. Bokeh doesn't need sharpness.

[audiobomber]

Both expectations and experience with other lenses factor in here. I really wanted the 18-135wr to be a winner, and I gave up three very nice lenses (16-45, 18-55, 55-300) to afford it. Under those conditions the IQ of my copy needed to suit me extremely well - it didn't, and I was very disappointed. At that time I also had a Sigma 18-200 that cost me under $200; it beat the 18-135 in every way but WR and quiet focus.

If your 18-135 didn't beat your 18-55 or Sigma 18-200 then clearly it was substandard.

[joe.penn]

And you've seen a lens that is so bad that the edges in a group picture were un-acceptable? You've seen portraits where extreme sharpness was necessary, at all? What? someone at the edge of the frame wanted to use the picture to check for zits? What happened to the good old days when our portrait lenses were bought to be soft, but meant to produce a pleasant, appealing softness? Sharpness wasn't even a consideration in a portrait lens. Rendition of subject was.

Ok, so the photographer should half-ass it, right?

Hey purchasing client that will use my photo in national publications for the $200k ad campaign for the summer, here is the photograph you payed me to produce and even though I knew my equipment was not up to par I still was able to produce this for you, don't worry about the edges because no one will be concerned about that.

Wonder what kind of responses a thread titled "Who Cares About Edge Sharpness Because I Don't" on a high volume forum of professionals somewhere - or, maybe Ben (benjikan here on the forums) can fill us in a little, I think he is shooting the "Vogue" cover soon wonder if he cares about edge sharpness...

And you've seen a lens that is so bad that the edges in a group picture were un-acceptable?

Not the lens, the photographs themselves - I have bounced plenty of them in my 20+ years of being in the publishing industry...

[normhead]

Not the lens, the photographs themselves - I have bounced plenty of them in my 20+ years of being in the publishing industry...

That's a completely different issue. You can produce soft edges with a good lens just by not paying attention to where you're focusing and how your clients are positioned. I was talking about lenses that would produce an image that was too soft at the edges, used by a photographer who could get the most out of it.

A person who can select lenses based on their ability to render the scene being shot - there's nothing half assed about that. It's the lazy way, relying on MTF numbers to evaluate lenses that's half assed. No one said anything about using equipment that isn't up to par. What I suggested was that just because a lens has great MTF numbers doesn't mean it's "up to par" on anything but the flat plane MTF charts used for tests. Otherwise you'd just be able to look at the MTF numbers for the lenses used and make your selection based on that. I do find your assertion that the equipment used is more important than the image produced somewhat troubling, given your position in the world. But then, I guess that's why I sell to the public directly. It's a not uncommon theme in the industry from what I can tell.

[cpk]

I use DxO as my initial raw converter of the pef files. I then move on to Lightroom with the originals converted by DxO to dng format. Please see posting #8 for a sample of DxO's effect on corner sharpness.

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/175026-da-18-1...treatment.html

[cali92rs]

I use DxO as my initial raw converter of the pef files. I then move on to Lightroom with the originals converted by DxO to dng format. Please see posting #8 for a sample of DxO's effect on corner sharpness.

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/175026-da-18-1...treatment.html

+1

DxO really does make optically mediocre lenses quite good for the lens/camera combos it supports...which fortunately includes a lot of the consumer zooms, where it is most needed.
The below lens was taken with the 18-55 WR, which no one would argue has better optics than the 18-135mm WR. But after DxO, it actually is a good performer.

[joe.penn]

I do find your assertion that the equipment used is more important than the image produced somewhat troubling

I think you have completely missed the point - there was never anything in my post that pointed to that. An image produced that is not consistent across the frame as should be (landscapes can fall in this also) will not win any awards, and that is based on the equipment - you may have produced the photograph to the best you could but that doesn't make up for the shortcomings of the lens itself.

Really bad trending stuff that is seen quite often here on the forums:

- Why worry about chromatic aberration when it can be fixed with a mouse click in LR
- I don't need to worry about framing this scene perfectly, as long as I am somewhat close I can crop it in
- I am not worried about the sharpness of that lens, I will sharpen in post
- I am not worried about a proper exposure, hell I will fix it in LR

Every thing noted above is bad with cropping being the least of the evil's (this is where MFT really comes into play). In short, the image produced is also dependent on the equipment you are using so I am not sure where this would be or sound troubling. I do understand that corners can be cut and a lot of this stuff is somewhat mute when it comes to certain things like wall prints and digital display(ing) but there are plenty of areas where these shortcomings make a huge impact and this is why a lot of photogs pay the big money for higher end lenses and this goes for all brands...


Edit:

After all of that, I will rephrase my one response:

Originally posted by LaurenOE
No one cares aesthetically what is at the extreme edges of a photograph
Response posted by joe.penn
Well, it is kind of important, and extremely important if you are shooting large group pictures...

Edge sharpness TO ME is pretty important as I am a seasoned pixel peeper by trade and I want my art to be consistently the same across the frame to lesson the chances of rejection.