[Rafalas]

Hi everyone,

I have a K10D with a few manual and automatic lenses. I'm thinking about getting the Tamron 17-50mm f2.8 XR Di-II because I'll like to upgrade my kit lens, the Pentax smc DA 18-55mm.

Apart of the higher constant aperture of the Tamron through all it's range, I'm more interested in the sharpness of it.

I'll really apreciate if someone who has both lenses could please do and submit two comparison photos of both lenses, from the same point of view, same focal and aperture, to compare the sharpness between them. Just one sample with each at something around 24mm will be enough.

I've read everywhere that the Tamron is a tack sharp lens, really good is all its range, but before buying one I will like to see how really different is comparing it with the Pentax kit lens, known to be a good lens overall.

I really apreciate the work and time of whoever can do this. Thanks a lot.

[Jasvox]

I own both and while I don't have 2 comparison photographs of the same subject, side by side...I can tell you that the Tamron 17-50 is by far a superior lens in the regards to sharpness, contrast and overall IQ. Quite frankly, the Pentax 18-55 (kit lens) is somewhat of a toy compared to the Tamron, but it's a worthy backup and better than competitor's kit lenses.

Jason

[Marc Sabatella]

Just one sample with each at something around 24mm will be enough.

Actually, it really wouldn't. While I doubt there would be any focal length or aperture where the 18-55 would win by any significant margin, there would almost certainly be focal lengths and apertures where it was really too close to call, others where the difference would be very clear in favor of the Tamron, and others where it would be somewhere between those extremes.

[stevebrot]

Actually, it really wouldn't. While I doubt there would be any focal length or aperture where the 18-55 would win by any significant margin, there would almost certainly be focal lengths and apertures where it was really too close to call, others where the difference would be very clear in favor of the Tamron, and others where it would be somewhere between those extremes.

1+ with Marc on this one.

I have seen some stellar work done with the 18-55 at moderate focal lengths and moderate apertures. It is one of the best value lenses on the globe. On the other hand, the Tamron should be able to provide consistently good results throughout its zoom range and would be my top pick for a fast wide-normal zoom for APS-C unless one wanted to pay the extra money for the DA* 16-50/2.8.

If the Tamron is available to you locally, you might want to go to the store and ask to shoot a few frames with your camera at different focal lengths. If the lens shines, you should be able to tell it from a short test.

Steve

[wallyb]

I can tell you for certain the 18-55 is very soft (actually, good resolution, but lots of coma) at 55, while the Tamron remains sharp as nails at 50mm.

[Rafalas]

Thanks everyone for your help.

I'm trying to estimate if it'll be worth to pay the 400+$ that the Tamron will cost in relation to the increase of quality that I'll appreciate in my photos. I don't work as a photographer at the moment, and I normally work with screen resolutions with maximum 2000 pixels on the bigger edge for my shots.
I wonder if the change will be significant using those resolutions to justify the spend.

What do you think?

[Pentaxor]

Thanks everyone for your help.

I'm trying to estimate if it'll be worth to pay the 400+$ that the Tamron will cost in relation to the increase of quality that I'll appreciate in my photos. I don't work as a photographer at the moment, and I normally work with screen resolutions with maximum 2000 pixels on the bigger edge for my shots.
I wonder if the change will be significant using those resolutions to justify the spend.

What do you think?

in my honest opinion, it is worth the investment. although I suggest that you should look for a used copy for a much cheaper price.

btw, with regards to my experience about the 18-55 (I have the WR version), here are my observations. it has weak contrast and ugly distortion at 18mm and soft at 55mm. although I find it best at 35mm where it really shines. 24-28mm is ok to good results. and Yes, whenever I use this lens, I most of the time post-process it more extensively. w/o post-processing, I would say it is only a mediocre-good lens, so nothing spectacular. I never used this lens wide open, I usually fix it at f8.

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Last edited by Pentaxor; 01-27-2010 at 01:25 PM.

[GeneV]

How long have you had the K10d/kit lens combo? What was your previous camera? I would shoot with it for a while before running out and buying a replacement. Without a doubt, there are differences, but there are so many other things to learn and improve before getting another lens.

I shot with my first DSLR and the kit lens for a little while, then made the mistake of going on the kit lens upgrade quest. I tried and even bought a couple of alternatives; however, the only lenses that made me immediately say "wow, this image is much better" were primes I had from my film days. I now realize that so many of the IQ issues I had were just the learning curve of autofocus digital cameras and all the features that had been added in the 20 years since I last purchased an SLR. Several years later, I am amusing myself by shooting with my K100d and first generation kit lens, and seeing how much better I am able to use that equipment.

It may be time to upgrade, but be sure you are getting the most from the equipment you have.

[Jewelltrail]

Dollar for dollar, there is no comparison, obviously, since the 18-55 gives a whole lot for just a few dollars. The answer to the question truly is up to you, even with all the excellent advice you have been given. Do what Steve said and:

stevebrot: If the Tamron is available to you locally, you might want to go to the store and ask to shoot a few frames with your camera at different focal lengths. If the lens shines, you should be able to tell it from a short test.

After doing this, then decide if what you see in the lens is worth what you will have to fork over to own it. Then, if you think it is, do what Pentaxor suggests:

although I suggest that you should look for a used copy for a much cheaper price.

Just make sure you really want the lens before you buy it. Good luck

[audiobomber]

in my honest opinion, it is worth the investment. although I suggest that you should look for a used copy for a much cheaper price.

I don't know that that's such a great idea considering the 17-50's reputation for backfocus/frontfocus problems.

[jerrymouse]

I don't know that that's such a great idea considering the 17-50's reputation for backfocus/frontfocus problems.

Yeah. I'm glad I bought a new one. I had awful frontfocus on my copy (I had to dial -220 in debug mode) and it's back for calibration right now.

[Pentaxor]

I don't know that that's such a great idea considering the 17-50's reputation for backfocus/frontfocus problems.

don't worry, I think 3 years is more than enough time before you can acquire a good copy that would last for more than just 1 year, w/o the risk of SDM failure. got no problem as long as it has a sufficient warranty and replacement.

[JnM_in_VT]

I haven't been able to compare the stock 18-55 to the Tamron 17-50 on my k20d yet (my Pentax mount copy arrives TODAY!) , but I'll tell you that I'd be VERY surprised if it wasn't sharper throughout the entire focal range. I had one for my Canon that I recently sold, and it was a great lens. Very sharp, great colors.... I can't wait to see how well my new one performs on my k20.

[Rafalas]

Again, thanks everyone for your great advice. I really appreciate them.

@JnM_in_VT: That will be the perfect moment to make those comparison shots

[JnM_in_VT]

I got my new Tammie today as expected! Gotta love it when UPS runs on time!

Now then, for my formal informal completely non-scientific comparison and opinion...
I took couple of quick comparison shots of my lampshade. Handheld. Yeah, I know... did I mention completely non-scientific? These are center crops, 100%.

The 1st on the left was taken with my shiny new Tamron 17-50

The 2nd on the right was taken with the stock 18-55

Both were at ISO 200, f/8.0, 1/60 @ 50mm with my K20d