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04-23-2010, 05:43 AM   #1
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DA 16-45mm vs 18-55mm II testing...

Hello Pentaxians, due in part to a recent discussion, I'd like to conduct a comprehensive test with using two DA 16-45 lenses and two 18-55 II Kit lenses to(hopefully) put to rest many of the discussions of the costs and benefits between these two well known choices.

So I wanted to ask if anyone could help with a good workflow and testing method that I might use to end-up with as useful a conclusion as possible.

I look forward to your comments and suggestions.
JB

04-23-2010, 09:47 AM   #2
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It seems a little fussy to get the focal lengths to exactly match on the wide end. I can get the camera to tell me the DA 16-45 is set at 18mm, but the photo is still a bit wider than the kit lens. The closer you can get the two lenses to have the same framing, the more reliable a sharpness test will be.

I like to see the sharpness tests with 100% crops side by side, both from the centers and the corners.

The DA 16-45 is supposed to be stronger at color, contrast, sharpness, large apertures and the wide end. It's supposed to be weaker at purple fringing. I would try to devise tests to show that. A landscape with a lot of color and a cloudless day should work. Since there are lab tests of these lenses already, some tests that look like real-world photos would be useful.

I have shot a lot of brick walls to look at distortion and they all look like brick walls to me. Bricks do make it easier to select the same 100% crop in multiple images and have detail, but not much color or contrast variation.

I seem to get more consistent results by setting a custom WB before each test. No matter how confident I am in focusing, I repeat the test to make sure my focusing is accurate on the test images. I use one lens as an exposure standard and get a good histogram at f8. After that, I don't use the meter, just calculate exposures from that standard. It should be easier to have both lenses register their data in EXIF. I have to keep notes to identify manual lenses.

I guess an AF test would be useful. I skip that because my camera's so old - maybe not the absolute slowest Pentax AF but close to the bottom.
04-23-2010, 11:06 AM   #3
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well I would suggest the following test parameters.

one method is done with in-camera jpeg, the other is RAW. custom image settings should be all set at 0. metering, aperture speed, and sensitivity should be the same inorder to show the difference. brick wall testing (controlled environment) and real world testing (outdoors) should be done. testing should involve something from close up to infinity with subjects from colorful architecture and landscapes to portraits or general photography. set focal lengths at 18,24,35 and 45 at apertures f5.6 and f8. images shot at close focus and infinity should include 100% crops.

during RAW processing, include the default or simple RAW-jpeg converted image and an enhanced image as well from both lenses.

I cannot provide some solid comparison with these lenses since I haven't used them in a side by side comparison, just the notion that the 16-45 is better due to the images I got from it when I had it for some test run. although I have extensively tested the 18-55 with other lenses and my findings are the ff.

M50/2 at 50mm is way sharper than the kitlens at all apertures including f8. color tone is warm though. the kitlens is has neutral tone.

55-300 @55mm renders better colors and resolution at the borders and have a slight sharpness.

FA35/2 at 35mm have equal center sharpness with the kitlens, but kitlens have some degree of softness at the borders. (note: I haven't tested this lens extensively enough, so there might be a degree or percentage of error or inconsistency with the results. I would do another test with both lenses). also note that the 18-55 is pretty strong at 35mm, as far an independent and individual real world use is concerned.

K28/3.5 at 28mm, I'm highly doubtful that even a good copy variant of the kitlens would beat this one.

FA50/1.7 - this is sharper than the kitlens

A50/1.2 - sharper than the kitlens

K55/1.8 = this is not even a debate especially at 55mm.

DA12-24 at 18mm and 24mm = I would rule out distortion since the kit lens is at a clear disadvantage here. kitlens doesn't have the degree of sharpness, contrast, detail and solid color that the 12-24 have. kitlens border and corner resolution are pretty weak at these focal lengths.

as for my conclusion, I would say the the 18-55 is only great at 35mm, and that is if you only shoot most of the time at that focal length but nothing more. the slow aperture can also pose a problem, btw.

Last edited by Pentaxor; 04-23-2010 at 11:15 AM.
04-23-2010, 02:17 PM   #4
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Have you seen what DXO Optics does for the kit lens? I sent my Sigma 17-70mm back after using the trial version of DXO.

04-23-2010, 02:40 PM   #5
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I am not one for testing methodologies. I just set up something I would normally shoot and have at it with various lenses, under exactly the same conditions I would normally encounter. The difficult thing, even in this approach, is definitely getting the exposures identical. Even slightly different light or slight change in camera direction can hurt -- this sort of thing is best done in manual mode.

EDIT: This might read like I am against more formal tests but I am not. I just don't do them myself nor think they are always as useful as some would make out.

Last edited by rparmar; 04-23-2010 at 05:28 PM.
04-23-2010, 03:09 PM   #6
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18-55 vs 16-45

Looking for a fair 18-55/16-45 comparision I've came across THIS today.
Maybe the methodology is not perfect but results stopped me from rapid purchase of 16-45 for bargain price.
HTH,

-- M.
04-23-2010, 05:19 PM   #7
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QuoteOriginally posted by HeavyD Quote
Have you seen what DXO Optics does for the kit lens? I sent my Sigma 17-70mm back after using the trial version of DXO.
this is not about 18-55 image pp enhancement, but rather lens IQ rendering comparison between 2 lenses.
04-23-2010, 05:24 PM   #8
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QuoteOriginally posted by rparmar Quote
I am not one for testing methodologies. I just set up something I would normally shoot and have at it with various lenses, under exactly the same conditions I would normally encounter. The difficult thing, even in this appraoch, is definitely getting the exposures identical. Even slightly different light or slight change in camera direction can hurt -- this sort of thing is best done in manual mode.
this could be tricky since the lens could meter differently. however, it would be interesting to see or show this difference between the 2 lenses and at the same the show an image that is equivalent in image exposure, disregarding the difference in exposure values.

04-23-2010, 09:17 PM   #9
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QuoteOriginally posted by rparmar Quote
I am not one for testing methodologies. I just set up something I would normally shoot and have at it with various lenses, under exactly the same conditions I would normally encounter. The difficult thing, even in this approach, is definitely getting the exposures identical. Even slightly different light or slight change in camera direction can hurt -- this sort of thing is best done in manual mode.

EDIT: This might read like I am against more formal tests but I am not. I just don't do them myself nor think they are always as useful as some would make out.
I think your method has a lot of advantages, especially for an individual evaluating a lens. You get the whole shooting experience and make a call on what works best. It is more difficult to present on the internet, because you may not be able to satisfy all readers about your methods. It does fill in what is missing from lab tests - using the lens for real world photos.

I admit that I can't do it that way, even for myself. I probably don't use the lenses enough even when not testing. When I do take a good photo with a lens, that is enough to brand that lens a keeper.
04-23-2010, 10:04 PM   #10
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Tripod & 2s lockup, of course. Shoot two subjects, a landscape and a cereal box. (Brick walls are not as revealing as print.) Camera set to default values for contrast, sharpening etc. I don't see any point in shooting raw, since you won't be processing. Shoot at 16, 18, 28, 45 and 55 mm and two apertures, wide open for the slower lens and f8. Use Av mode and let the camera choose metering. Show the whole photo and 100% crops of the center and a corner.

I did this the other day with the 18-55mm DAL and 18-250mm. I used the lens correction feature because that's how I use them on the K-x. There were no significant differences except for more vignetting in the 18-250 at 18mm wide open (a known problem). The 18-250 had slightly better contrast wide open at 18mm. With no lens correction the superzoom would have shown more distortion at the wide end.

Last edited by audiobomber; 04-24-2010 at 07:05 AM.
04-24-2010, 05:20 AM   #11
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QuoteOriginally posted by Just1MoreDave Quote
I think your method has a lot of advantages, especially for an individual evaluating a lens. You get the whole shooting experience and make a call on what works best. It is more difficult to present on the internet, because you may not be able to satisfy all readers about your methods. It does fill in what is missing from lab tests - using the lens for real world photos.
I like looking at strict lens tests as well, MTF measures and so on. I'm a geek; I can't help it! But I never take even those as gospel, since testing methodologies differ.

But for evaluating lenses I look at what people have been able to shoot with them. If this is in "controlled" environments, so much the better. I've done a few comparisons like this myself and posted them on the forum. From the feedback I get, I know it helps people.

Looking forward to this one!
09-07-2010, 05:13 PM   #12
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I used to be very precise in my testing, shooting newsprint and such; thing is I always forgot to lock down some variable in my test (iso, or metering, or whatnot) and made the results technically useless. I finally gave it up and started shooting my local wooden streetlamp-post, and checked the grain. Does it look good? Yep, this lens passes Another lens will do better, but if it passes that's enough. I did a few shootouts and found better lenses over time, but I cannot beat myself up over it if that means taking more test shots than 'real' ones. Took me a while to reach that point though; good luck as you progress on your path & I'm sure I will scrutinize your results anyway!

Some days I got to check more than wood-grain:

Last edited by jimr-pdx; 09-07-2010 at 05:33 PM. Reason: it sucked before
09-07-2010, 05:53 PM   #13
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Warning: necro-thread!

Which must make that a necro-rodent.
09-07-2010, 09:41 PM - 1 Like   #14
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By coincidence, I just posted a quick 18-55WR vs 16-45 comparison a few hours ago.

I learned a long time ago I don't have the resources or smarts to TEST much of anything but I do make subjective, relative evaluations of tools on a pass/fail basis. There's just too many arbitrary variables in practice even though it's nice to start with the confidence you have the best tool available at the time.

I finally acquired a WR kit lens for the expressed purpose of having peace of mind in foul weather. If I can get it to produce satisfactory results with all the skill, knowledge and effort I'm will to allocate to that tool and a given image, it's a keeper. That includes any pre- or post-processing decisions I might choose to use with it just as choice of film type, filters, and darkroom shenanigans affected film.

After disposing of two Type-I kit lenses, this one exceeded my expectations. While it won't supplant my DA 16-45 it has a place in the tool box. I'm happy with it. Now it's up to me to use it to its potential and when rain drops are fallin' on my head in the canoe I'm sure it'll contribute to the best possible outcome.

H2

Besides, testing just interferes with LBA. Comparisons, on the other hand, provide enabling excuses.
09-08-2010, 05:39 AM   #15
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QuoteOriginally posted by pacerr Quote
Besides, testing just interferes with LBA. Comparisons, on the other hand, provide enabling excuses.
+1

(oops, message too short)
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