Pentax DA 21 - Soft Wide Open?

trixtroll · 08-08-2021, 07:49 AM

I read a LOT of reviews on the DA 21 and I didn't think center softness wide open was a common issue. Am I crazy or is this normal for this lens?

I shot a couple test shots compared to my trusty old Pentax-A 28 f2.8 and the Pentax-DA 21 LTD is a little disappointing wide open.....Very happy with it closed down to F5 though.

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normhead · 08-08-2021, 07:59 AM - **5 Likes**

Lenses built to be light weight and portable tend to be like that. It takes a lot of weight to adjust for sharp edges. I use the 21 ltd. for it's rendering in pastel daylight scenes. It doesn't handle contrast well, it's not edge to edge sharp. If that's what you bought it for you bought the wrong lens. Tha being said, at reduced size it's rendering is wonderful in 3D scenes with transitions and out of focus areas. I wouldn't even point mine at a brick wall. It would be an insult to the lens designers, in that, they didn't design it for brick walls. It's a "Lens designed for the way people take pictures, not for the test charts" lens, as are all the older limiteds.

The less weight you design a lens for, the more compromises you have to make.

That being said, the lens should have excellent center sharpness, with ƒ3.2 to ƒ8 being pretty much indistinguishable in the middle.

**ThorSanchez** · 08-08-2021, 08:01 AM - **1 Like**

It's hard to tell at web sizes how soft your photos are, but the first one does look a little blurry. Are you sure that the auto-focus fine tune is really dialed in?

The attached file here I just took at my desk with the HD DA 21mm LTD at f/3.2. It's a 100% crop. Aside from maybe being a touch back-focused it looks reasonably sharp to me.

Jonathan Mac · 08-08-2021, 08:10 AM

I regard my DA 21mm as sharp enough wide open, at least in the central 50% or so of the image, that's on a K3. I use it there without worries if light is low or I want shallow DoF for a close-up or portrait.

For real sharpness across the frame I prefer to stop it down to f/4.5 at least.

normhead · 08-08-2021, 08:16 AM

Originally posted by ThorSanchez

It's hard to tell at web sizes how soft your photos are, but the first one does look a little blurry. Are you sure that the auto-focus fine tune is really dialed in?

The attached file here I just took at my desk with the HD DA 21mm LTD at f/3.2. It's a 100% crop. Aside from maybe being a touch back-focused it looks reasonably sharp to me.

That's what I'd try first. Doing a lens adjustment solves a lot of problems. Especially if it's soft wide open but not stopped down. Stopped down the need for a slight adjustment is masked by the DoF. Wide open, the focus needs to be precise.

AfterPentax Mark II · 08-08-2021, 08:16 AM

Originally posted by normhead

I use the 21 ltd. for it's rendering in pastel daylight scenes. It doesn't handle contrast well, it's not edge to edge sharp.

I did not realize it at the time, but you perfectly illustrated why I did not like the lens when I had it last year. It was recommended but when taking pictures with it, I was quite disappointed. And I notice this in some other lenses as well, one could get the idea that the lens was designed for specific purposes and not general photograpy. Luckily I could return it and got a full refund.

normhead · 08-08-2021, 08:28 AM - **2 Likes**

Originally posted by AfterPentax Mark II

I did not realize it at the time, but you perfectly illustrated why I did not like the lens when I had it last year. It was recommended but when taking pictures with it, I was quite disappointed. And I notice this in some other lenses as well, one could get the idea that the lens was designed for specific purposes and not general photograpy. Luckily I could return it and got a full refund.

When the lens was designed, that was "general purpose photography" at the time. Test charts have definitely changed what's acceptable for general purpose photography. The good thing now is we have choice, we can buy the DA 21 ltd if we like it, or want a portable lens. The new 21 that's coming will be a modern weight and performance. We'll have a choice. I like the 21 because when I am out with a telephoto, 60-250, 55-300, DA*200, etc. I can throw it in the bag "just in case" with no weight penalty. But I rarely actually use it. It provides great peace of mind though.

Last edited by normhead; 08-08-2021 at 08:41 AM.

Kozlok · 08-08-2021, 10:33 AM

As a first step, you could try focusing in live view at f3.2 and then compare the shot to focusing using the viewfinder and see if that sharpens up the middle. If it does, then a focus adjustment will cure your ills.

Here's a closeup wide open with the focus nailed pretty well. I'd say it's a lot sharper than what you presented. Also one of my tie, and in the in-focus zone again it is a lot sharper than what you've shown. Full resolution on my Flickr page. My money is on mis-focusing since it looks great at f4.

trixtroll · 08-08-2021, 10:58 AM

Originally posted by normhead

Lenses built to be light weight and portable tend to be like that. It takes a lot of weight to adjust for sharp edges. I use the 21 ltd. for it's rendering in pastel daylight scenes. It doesn't handle contrast well, it's not edge to edge sharp. If that's what you bought it for you bought the wrong lens. Tha being said, at reduced size it's rendering is wonderful in 3D scenes with transitions and out of focus areas. I wouldn't even point mine at a brick wall. It would be an insult to the lens designers, in that, they didn't design it for brick walls. It's a "Lens designed for the way people take pictures, not for the test charts" lens, as are all the older limiteds.

The less weight you design a lens for, the more compromises you have to make.

That being said, the lens should have excellent center sharpness, with ƒ3.2 to ƒ8 being pretty much indistinguishable in the middle.

I wouldn’t normally point it at a brick wall, but it was the best test subject I had on hand after shooting some street photos this morning.

I may have to mess with the focus adjustment, but overall it’s pretty good past f4.

**c.a.m** · 08-08-2021, 11:07 AM

Originally posted by trixtroll

may have to mess with the focus adjustment,

Would it be worth the time to retake the brick wall pics using manual focus with Live View?

- Craig

house · 08-08-2021, 11:15 AM

Originally posted by trixtroll

I wouldn’t normally point it at a brick wall,

Some people do, to to great effect.

So it's a fair enough test.

spread from "Industrial Facades" by Bernd and Hilla Becher

zapp · 08-08-2021, 01:29 PM

Brick wall is great for tests, but brick wall at close range and aperture wide open is a problem for such a small lens.

MadBill · 08-08-2021, 02:19 PM

I have never been satisfied with the performance of this lens wide open. Not just sharpness, but also contrast and saturation. I have always wished they had made it a little faster and a little better wide open, and of course, a little bigger. But when it was released in 2006 camera resolution was 6-10MP, so technology has changed, but also expectations. Today, if I am going to carry the size and weight of a Pentax DSLR (vs a cellphone or m43) I am looking for excellent performance. I am looking forward to seeing the new 21mm when it is released. I believe Ricoh has indicated they will be developing some prime lenses that are smaller and lighter than the 50mm and 85mm f/1.4 lens. Perhaps a new generation of Limiteds?

ZombieArmy · 08-08-2021, 04:09 PM

First photo looks straight up out of focus. I don't think I own a single lens besides some no name 135mm that performs THAT badly.

trixtroll · 08-08-2021, 04:49 PM

I’ve been playing with it more and the KP is really struggling to focus with that lens through the viewfinder, but live view performs much better.

Starting to wonder if something is going on with the KP and I just haven’t noticed the issue before.

08-08-2021, 07:59 AM - 5 Likes	#2
normhead Pentaxian Join Date: Jun 2007 Location: Near Algonquin Park Photos: Gallery \| Albums Posts: 40,451	Lenses built to be light weight and portable tend to be like that. It takes a lot of weight to adjust for sharp edges. I use the 21 ltd. for it's rendering in pastel daylight scenes. It doesn't handle contrast well, it's not edge to edge sharp. If that's what you bought it for you bought the wrong lens. Tha being said, at reduced size it's rendering is wonderful in 3D scenes with transitions and out of focus areas. I wouldn't even point mine at a brick wall. It would be an insult to the lens designers, in that, they didn't design it for brick walls. It's a "Lens designed for the way people take pictures, not for the test charts" lens, as are all the older limiteds. The less weight you design a lens for, the more compromises you have to make. That being said, the lens should have excellent center sharpness, with ƒ3.2 to ƒ8 being pretty much indistinguishable in the middle. Last edited by normhead; 08-08-2021 at 08:10 AM.

08-08-2021, 08:16 AM	#6
AfterPentax Mark II Pentaxian Join Date: Mar 2021 Posts: 1,465	Originally posted by normhead I use the 21 ltd. for it's rendering in pastel daylight scenes. It doesn't handle contrast well, it's not edge to edge sharp. I did not realize it at the time, but you perfectly illustrated why I did not like the lens when I had it last year. It was recommended but when taking pictures with it, I was quite disappointed. And I notice this in some other lenses as well, one could get the idea that the lens was designed for specific purposes and not general photograpy. Luckily I could return it and got a full refund. Last edited by AfterPentax Mark II; 08-08-2021 at 08:19 AM. Reason: to large a quote

08-08-2021, 11:07 AM	#10
c.a.m Site Supporter Join Date: Jan 2013 Location: Ottawa, Canada Photos: Gallery \| Albums Posts: 4,191	Originally posted by trixtroll may have to mess with the focus adjustment, Would it be worth the time to retake the brick wall pics using manual focus with Live View? - Craig Last edited by c.a.m; 08-08-2021 at 11:14 AM.

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08-08-2021, 08:10 AM	#4
Jonathan Mac Pentaxian Join Date: Apr 2009 Location: Madrid, Spain Posts: 10,910	I regard my DA 21mm as sharp enough wide open, at least in the central 50% or so of the image, that's on a K3. I use it there without worries if light is low or I want shallow DoF for a close-up or portrait. For real sharpness across the frame I prefer to stop it down to f/4.5 at least.

08-08-2021, 08:16 AM	#5
normhead Pentaxian Join Date: Jun 2007 Location: Near Algonquin Park Photos: Gallery \| Albums Posts: 40,451	Originally posted by ThorSanchez It's hard to tell at web sizes how soft your photos are, but the first one does look a little blurry. Are you sure that the auto-focus fine tune is really dialed in? The attached file here I just took at my desk with the HD DA 21mm LTD at f/3.2. It's a 100% crop. Aside from maybe being a touch back-focused it looks reasonably sharp to me. That's what I'd try first. Doing a lens adjustment solves a lot of problems. Especially if it's soft wide open but not stopped down. Stopped down the need for a slight adjustment is masked by the DoF. Wide open, the focus needs to be precise.

08-08-2021, 08:28 AM - 2 Likes	#7
normhead Pentaxian Join Date: Jun 2007 Location: Near Algonquin Park Photos: Gallery \| Albums Posts: 40,451	Originally posted by AfterPentax Mark II I did not realize it at the time, but you perfectly illustrated why I did not like the lens when I had it last year. It was recommended but when taking pictures with it, I was quite disappointed. And I notice this in some other lenses as well, one could get the idea that the lens was designed for specific purposes and not general photograpy. Luckily I could return it and got a full refund. When the lens was designed, that was "general purpose photography" at the time. Test charts have definitely changed what's acceptable for general purpose photography. The good thing now is we have choice, we can buy the DA 21 ltd if we like it, or want a portable lens. The new 21 that's coming will be a modern weight and performance. We'll have a choice. I like the 21 because when I am out with a telephoto, 60-250, 55-300, DA200, etc. I can throw it in the bag "just in case" with no weight penalty. But I rarely actually use it. It provides great peace of mind though. Last edited by normhead; 08-08-2021 at 08:41 AM.*

08-08-2021, 10:33 AM	#8
Kozlok Pentaxian Join Date: Jun 2012 Location: Albuquerque Photos: Gallery Posts: 3,148	As a first step, you could try focusing in live view at f3.2 and then compare the shot to focusing using the viewfinder and see if that sharpens up the middle. If it does, then a focus adjustment will cure your ills. Here's a closeup wide open with the focus nailed pretty well. I'd say it's a lot sharper than what you presented. Also one of my tie, and in the in-focus zone again it is a lot sharper than what you've shown. Full resolution on my Flickr page. My money is on mis-focusing since it looks great at f4.

08-08-2021, 10:58 AM	#9
trixtroll Pentaxian Join Date: Sep 2009 Location: Dayton, OH Posts: 403 Original Poster	Originally posted by normhead Lenses built to be light weight and portable tend to be like that. It takes a lot of weight to adjust for sharp edges. I use the 21 ltd. for it's rendering in pastel daylight scenes. It doesn't handle contrast well, it's not edge to edge sharp. If that's what you bought it for you bought the wrong lens. Tha being said, at reduced size it's rendering is wonderful in 3D scenes with transitions and out of focus areas. I wouldn't even point mine at a brick wall. It would be an insult to the lens designers, in that, they didn't design it for brick walls. It's a "Lens designed for the way people take pictures, not for the test charts" lens, as are all the older limiteds. The less weight you design a lens for, the more compromises you have to make. That being said, the lens should have excellent center sharpness, with ƒ3.2 to ƒ8 being pretty much indistinguishable in the middle. I wouldn’t normally point it at a brick wall, but it was the best test subject I had on hand after shooting some street photos this morning. I may have to mess with the focus adjustment, but overall it’s pretty good past f4.

08-08-2021, 11:15 AM	#11
house Pentaxian Join Date: May 2015 Photos: Albums Posts: 3,306	Originally posted by trixtroll I wouldn’t normally point it at a brick wall, Some people do, to to great effect. So it's a fair enough test. spread from "Industrial Facades" by Bernd and Hilla Becher

08-08-2021, 01:29 PM	#12
zapp Pentaxian Join Date: Jul 2011 Posts: 2,388	Brick wall is great for tests, but brick wall at close range and aperture wide open is a problem for such a small lens.

08-08-2021, 02:19 PM	#13
MadBill Forum Member Join Date: Dec 2018 Posts: 76	I have never been satisfied with the performance of this lens wide open. Not just sharpness, but also contrast and saturation. I have always wished they had made it a little faster and a little better wide open, and of course, a little bigger. But when it was released in 2006 camera resolution was 6-10MP, so technology has changed, but also expectations. Today, if I am going to carry the size and weight of a Pentax DSLR (vs a cellphone or m43) I am looking for excellent performance. I am looking forward to seeing the new 21mm when it is released. I believe Ricoh has indicated they will be developing some prime lenses that are smaller and lighter than the 50mm and 85mm f/1.4 lens. Perhaps a new generation of Limiteds?

08-08-2021, 04:09 PM	#14
ZombieArmy Pentaxian Join Date: Jun 2014 Location: Florida Posts: 3,210	First photo looks straight up out of focus. I don't think I own a single lens besides some no name 135mm that performs THAT badly.

08-08-2021, 04:49 PM	#15
trixtroll Pentaxian Join Date: Sep 2009 Location: Dayton, OH Posts: 403 Original Poster	I’ve been playing with it more and the KP is really struggling to focus with that lens through the viewfinder, but live view performs much better. Starting to wonder if something is going on with the KP and I just haven’t noticed the issue before.