[bdery]

I have found one initial thread on this topic, but it's already old:

DA 16-85 and DFA 28-105 differences and my initial assessment - PentaxForums.com

I've been using the 16-85 as my workhorse for a good many years. Even when I got the K-1, the 16-85 remained with me, in good part because I had nothing which gave me an equivalent to the lens' wide angle on FF. However, managing the crop factor has become bothersome, especially since I modified my 60-250 for full frame.

Fast forward, I now have the FA 20-35 and it covers the wide angle pretty well. I wouldn't miss the 16-85's wide end all that much, and the tele end isn't an issue either (I got primes and can crop from 36 MP). So the 28-105 is beginning to have more appeal. It's also a tad smaller.

Even though my lineup of primes is better than the 16-85, that lens has always been reliable and trustworthy. I wonder how the 28-105 compares to it optically.

Side-by-side images are a lot to ask for of course, but any opinion would be welcome. Thanks!

[jddwoods]

Sorry, I cannot give you a comparison between these two zooms since I do not have the DFA 28-105. I will be very interested in seeing what responses you get. I was on the fence a year and a half ago trying to decide between getting a DFA 28-105 or the 16-85 as my workhorse zoom on my K-3. Unfortunately my budget was for a used lens and there were no used copies of the 28-105 in my budget available. I was leaning toward the 28-105 based on it being FF in case I decide to upgrade in the near future. I did find a like new used 16-85, bought it, and have been using it for the last 18 months. I am very happy with the 16-85, it is solid, sharp and very versatile, everything I wanted in a workhorse zoom.
I am curious what primes you have that are sharper than the 16-85 and if you are comparing in crop mode. Comparing the 16-85 to the primes that I have: DA 21, 40 and 70 limiteds and F 28 f2.8 and FA 50 f1.7 I find the only one that I can really say is sharper is the DA 70 Limited and not by much. Regarding the 28-105, from what I have seen the reviews on it are really positive so I am sure it would be a great choice. I would think on my K-3 it would easily be as good, possibly better, than the 16-85.
Good luck with your choice

[northcoastgreg]

I own both the DA 16-85 and the DFA 28-105. However, I've only shot the 16-85 on APS-C and the 28-105 on the K-1. The 28-105 on the K-1 will definitely out-perform the 16-85 on an APS-C camera (at least a mid-apertures where I mostly shoot). How much of that is due to the lens and how much is due to larger sensor might be a point of contention. However, I do suspect the 28-105 is a little better. It seems to have better edge to edge sharpness throughout its entire range (on FF) than the DA 16-85 does on APS-C. Contrast is about the same. The 28-105 seems (I'm merely guessing here) to have a bit more distortion and light fall-off toward the edges.

Perhaps a more informative point of reference would involve comparing the DFA 28-105 to the FA 20-35, which I also own. The DFA 28-105 is very slightly sharper in the center (at, say, F 11). It's sharper at the edges and significantly sharper in the corners. The DFA also features slightly better contrast and richer color signature than the FA lens.

[bdery]

am curious what primes you have that are sharper than the 16-85 and if you are comparing in crop mode.

My lenses are listed in my signature...

I did not say "sharper", I said optically better. Sharpness is a part of that, but also are rendering, colours, bokeh, aberrations, distortion, etc.

For the record, the lenses I can compare it with are the DA21, DA40, FA43, FA77, DFA 100 macro WR, DA 60-250. I really like the 16-85, it's reliable and with few flaws, what it lacks when compared with those other lenses is the small magical touch...

However, I've only shot the 16-85 on APS-C and the 28-105 on the K-1

That's the intended use case, so it's fair, and useful.

How much of that is due to the lens and how much is due to larger sensor might be a point of contention.

If you use an APS-C sensor with more than 16 MP, resolution per surface area is actually higher on APS-C. So comparing sharpness between the two skews the interpretation in favor of the 16-85.

However, I do suspect the 28-105 is a little better. It seems to have better edge to edge sharpness throughout its entire range (on FF) than the DA 16-85 does on APS-C. Contrast is about the same. The 28-105 seems (I'm merely guessing here) to have a bit more distortion and light fall-off toward the edges.

If I understand correctly, the differences would be in favor of the 28-105, but minimal in all cases? In essence, optically I would be on familiar ground and wouldn't risk losing anything?

Perhaps a more informative point of reference would involve comparing the DFA 28-105 to the FA 20-35, which I also own. The DFA 28-105 is very slightly sharper in the center (at, say, F 11). It's sharper at the edges and significantly sharper in the corners. The DFA also features slightly better contrast and richer color signature than the FA lens.

That's interesting, as I've acquired the 20-35 recently. It's a lens I like, but find needs some time to learn. It's not as easy to use as the DA21 for instance. For starters, my copy needed AF adjustment, second I find it a bit overly contrasted. But it's also able to create beautiful starbursts, is as sharp as the DA21 in the APS-C area (I agree it's not as sharp in the corners), its AF is pretty good and it doesn't create much distortion. I should probably shoot more in RAW and benefit from the extra dynamic range with this lens.

Keep the comments coming! They are informative, and may have me sell my 16-85 sometime in the future.

[northcoastgreg]

If you use an APS-C sensor with more than 16 MP, resolution per surface area is actually higher on APS-C. So comparing sharpness between the two skews the interpretation in favor of the 16-85.

The only way to really determine which lens is sharper is to shoot on the same APS-C camera and compare. A 24 MP APS-C sensor may provide more resolution per surface area, but the FF sensor requires less magnification to project the consequent image on a computer screen or across a print. To compare across formats, probably the best way to do it would be to take the exact same image with each lens on its respect format, then downsize the FF image to equal the APS-C image in total resolution, and then compare at 100%.

If I understand correctly, the differences would be in favor of the 28-105, but minimal in all cases? In essence, optically I would be on familiar ground and wouldn't risk losing anything?

The differences, at least in terms of resolution, would definitely be in favor of the DFA 28-105/K-1 combination, largely due to DFA's ability to project an image across a larger surface area. It's difficult to quantify the difference, but I would say that it's at least a little more than minimal. Also, the DFA 28-105, as far as I can tell (I haven't done any rigorous testing) seems to feature better edge to edge sharpness at longer focal lengths than my copy of the DA 16-85. For that reason, I'm inclined to regard the DFA as the better lens overall. As a landscape photographer, I very much appreciate high quality, slow aperture glass, of which both the DA 16-85 and the DFA 28-105 constitute superb exemplars.

Here are a couple sample images from the DFA:





And here's a flickr album of full resolution images taken with the lens: Pentax HD DFA 28-105 f3.5-5.6

[MaineNative]

I have both lenses. I took some shots on my K-1 using full frame for both lenses, f/5.6, @85 mm, ISO 100. The center of both lenses are incredibly sharp. I did find the 28-105 is a little softer on the edge (ignoring the vignetting) but still pretty good. I was using the 16-85 on my K-5 and then got the 28-105 when I bought the K-1. I think the quality is comparable between the two lenses, but I do wish the full-frame was 24-105 for a little wider field of view. (Unfortunately I don't have a good account for posting the full-size pictures.)

[bdery]

I do wish the full-frame was 24-105 for a little wider field of view.

I wouldn't even be asking these questions if the lens was 24-105...

I think the quality is comparable between the two lenses

Great!

I'm inclined to regard the DFA as the better lens overall

Good.

As a landscape photographer, I very much appreciate high quality, slow aperture glass, of which both the DA 16-85 and the DFA 28-105 constitute superb exemplars.

I understand what you mean.

These comments answer my question pretty well : the upgrade would make sense and I wouldn't lose anything significant. I'll quite possibly be listing my 16-85mm.

[mtngal]

Rather than start a new thread on this topic, I thought maybe changing the scope of this one slightly would make sense. I'm interested in the same two lenses, but starting with the 28-105, not the 16-85.

In my case, I really want a lens that will be as good on a KP as the 28-105 is on a K1, covering wide as well as medium telephoto. I want to use it for tourist walk-about and landscape, so speed isn't an issue (I have primes if I need extra speed).

As background, up until this spring I was using the K1 and 28-105 almost exclusively, loved that combination and didn't miss my fast primes at all. I bought the KP as a dedicated telephoto set-up for a trip to Alaska and as a back-up camera to the K1. I found myself in Alaska using the KP as a single walk-about camera because the ergonomics work better for me. But I got frustrated as the 28-105 isn't as wide as I wanted (or was used to) and I didn't want to keep changing lenses while playing the tourist.

Would the 16-85 on the KP be the best solution to match the what I have with the K1/28-105 combination? Or is there a different lens I should be looking at?

[timb64]

Rather than start a new thread on this topic, I thought maybe changing the scope of this one slightly would make sense. I'm interested in the same two lenses, but starting with the 28-105, not the 16-85.

In my case, I really want a lens that will be as good on a KP as the 28-105 is on a K1, covering wide as well as medium telephoto. I want to use it for tourist walk-about and landscape, so speed isn't an issue (I have primes if I need extra speed).

As background, up until this spring I was using the K1 and 28-105 almost exclusively, loved that combination and didn't miss my fast primes at all. I bought the KP as a dedicated telephoto set-up for a trip to Alaska and as a back-up camera to the K1. I found myself in Alaska using the KP as a single walk-about camera because the ergonomics work better for me. But I got frustrated as the 28-105 isn't as wide as I wanted (or was used to) and I didn't want to keep changing lenses while playing the tourist.

Would the 16-85 on the KP be the best solution to match the what I have with the K1/28-105 combination? Or is there a different lens I should be looking at?

The 16-85.....

DA 16-85 WR,show us what it can do. - PentaxForums.com

....or the 18-135?

DA 18-135 WR, Show us what it can do - PentaxForums.com

Having owned both,my personal preference is the former,YMMV!

The choice is yours.

[normhead]

The 16-85.....

DA 16-85 WR,show us what it can do. - PentaxForums.com

....or the 18-135?

DA 18-135 WR, Show us what it can do - PentaxForums.com

Having owned both,my personal preference is the former,YMMV!

The choice is yours.

Good answer.

Tess loves the 28-105 on her K-5. She's always taking dibs on it when we go out. I keep trying to talk her into the 16-85, she's tried the 18-135 and it didn't meet her standards and her Tamron 17-50 has become unpredictable. Sometimes it's de-centered sometimes it's not. But we don't have it yet (christmas is coming) I may have more to say in March after my tax return shows up.

[timb64]

Good answer.

Glad it meets with your approval

[MaineNative]

I own both the 16-85 and the 18-135. The 18-135 is a little smaller and lighter than the 16-85, so that may affect whether you want to use it as a walk-around lens. However, once I bought the 16-85, I completely stopped using the 18-135. The little wider FOV and extra sharpness was worth the extra weight, but I did need to upgrade my shoulder bag to hold the larger lens. One other benefit of the 18-135 is that it takes the same sized filter as the 28-105. The 16-85 takes a larger filter.

[northcoastgreg]

Would the 16-85 on the KP be the best solution to match the what I have with the K1/28-105 combination? Or is there a different lens I should be looking at?

Yes, the DA 16-85 on KP is the closest solution to match the K1 and the DFA 28-105, particularly if you want something that goes a little wider. Admittedly, 16mm on APS-C isn't much wider than 28mm on FF, but it is wider. There's no standard zoom, however, that goes wider.

[mtngal]

Yes, the DA 16-85 on KP is the closest solution to match the K1 and the DFA 28-105, particularly if you want something that goes a little wider. Admittedly, 16mm on APS-C isn't much wider than 28mm on FF, but it is wider. There's no standard zoom, however, that goes wider.

Thanks!

I’m not concerned with something wider than 16, I have other options if I really want to go wider (DA15, DA 12-24 and for fun but rarely used DA 10-17). I originally figured I would just use the 28-105 with the KP, but found the field of view too limiting on the wide end. My first thought was to use that as an excuse to buy the DA 20-40 Ltd, but as much as I would like that lens, I’d still be changing lenses all the time and carrying a heavier camera bag than I should most of the time (it’s the heavy camera bag that bothers me the most).

I didn’t care for the 18-135 the one time I shot with one. It was OK, but that was about it, that’s why I’m not considering it, and wondered if the 16-85 was better. It sounds like it is.

The funny thing is that the only reason I bought the 28-105 in the first place is that I got it for half price with the K1 at a photo show. I was very surprised just how good that lens is, and how perfect it is for my needs with the K1 once I retired and bought an RV. Before that I had been been using mostly primes.

So it sounds like the 16-85 would be the best lens to meet what I really want/need.

[bdery]

Rather than start a new thread on this topic, I thought maybe changing the scope of this one slightly would make sense. I'm interested in the same two lenses, but starting with the 28-105, not the 16-85.

In my case, I really want a lens that will be as good on a KP as the 28-105 is on a K1, covering wide as well as medium telephoto. I want to use it for tourist walk-about and landscape, so speed isn't an issue (I have primes if I need extra speed).

As background, up until this spring I was using the K1 and 28-105 almost exclusively, loved that combination and didn't miss my fast primes at all. I bought the KP as a dedicated telephoto set-up for a trip to Alaska and as a back-up camera to the K1. I found myself in Alaska using the KP as a single walk-about camera because the ergonomics work better for me. But I got frustrated as the 28-105 isn't as wide as I wanted (or was used to) and I didn't want to keep changing lenses while playing the tourist.

Would the 16-85 on the KP be the best solution to match the what I have with the K1/28-105 combination? Or is there a different lens I should be looking at?

Having purchased the 28-105 from a forum member, I can confirm that it's really the equivalent of the 16-85 on FF. Both lenses offer the same experience, sharpness and general quality.

The sad thing is that the copy I purchased suffers from inconsistent focus inaccuracies. That is to say, if I fine-tune AF for, say, 50-60mm, it becomes wildly off at other focal lengths. And it's also inconsistent depending on the subject distance. I'm in communication with the seller and we'll see how it goes, when focusing manually or via live view it works well, so it's not glass damage inside the lens. Hopefully it's possible to repair it.

MTNGAL, if I wasn't suffering from this problem, I'd be putting my 16-85 up for sale. If you're in no hurry I can get back to you when things are sorted out.