[Jewelltrail]

aweir

Compared to the image quality of the Tamron 17-50, I really don't see why anyone would spend $200 more for quieter focus, especially since the speed isn't that much faster. Maybe that's the pentax way of life.

And even though I have a mild selection of Pentax lenses, the DA * to me just doesn't seem worth the price difference right now. Maybe once they correct the issues with them. A * lens with QC issues?? photozpne wasn't too impressed with it.

The Da has a few advantages over the Tamron:

quieter focus--the Pentax name--weather sealing

I really wanted the Da when I joined Pentax with my purchase of the K20d. The main reason was because I hike and wanted weather sealing--seriously wanted. In fact, one of the key reasons I chose the K20 over the competition was its excellent weather sealing. My research of the 2 lenses, which was extensive (usually is for me), led me to conclude the Tamron had better overall image quality. So it was hard for me to pay more for a lens that, though weather sealed, underperformed in image quality to a 3rd-party vendor.

I decided, as much as weather sealing was important to me, I would buy the Tamron and be very careful when hiking. I also decided I could live with the well-documented noise of the Tamron auto-focus system. Brand loyalty is not a commodity in which I choose to invest, so at least one part of the equation was easy to solve. So I own the Tammy. However, many people chose the Da, and I can understand why.

Look out if Tamron ever weather seals it!

[aweir]

Actually the speed (not AF) and IQ of the Tamron 17-50 almost makes me second guess whether I need a prime at all in that range.

[Derridale]

You can put me down as another LBA sufferer who has both the 16-50 and the 50-135 DA* lenses - and they are BOTH excellent copies. No complaints about either of them.

[nulla]

You can put me down as another LBA sufferer who has both the 16-50 and the 50-135 DA* lenses - and they are BOTH excellent copies. No complaints about either of them.

I am another Aussie in exactly the same boat

[EricT]

aweir

The Da has a few advantages over the Tamron:

quieter focus--the Pentax name--weather sealing

The weather sealing was what sealed the deal for me. Also, a few more things you didn't mention:

• one extra mm is nice,
• the Pentax has quick-shift focus which I use all the time, and
• the Tamron has very high field curvature at the wide end.

The Pentax is really the only choice in this range, at least for me.

[OrenMc]

Okay. I am not very good at testing but this is a couple shots I took today. I thought I was past the BF/FF issue but it looks like the qiuck test I did earlier was too quick.

First shot is without any adjustments. The focus was on the buckle on the belt between the airtanks and hose connections around it waist.

TEST


Second shot is +10 adjustment. Noticablely sharper.

TEST1


Full sizes can be found here


I appreciate everyones opinions and sugestions. I am wondering a couple things now. (1) If I am at max adjustment does it still need more adjustment? Am I getting full potential?
(2) Would it be worth to keep and send in to Pentax for adjustments? ( no warrenty ) Or would I be better off just getting a new one?

Have any of you sent lenses in after warrenty expired and what would be approximate cost?

If the adjustments I did today is the fix then I am a happy person. I will have to do a little more shotting to short that out.

Thanks all

[Jewelltrail]

EricT: The weather sealing was what sealed the deal for me. Also, a few more things you didn't mention:
one extra mm is nice,
the Pentax has quick-shift focus which I use all the time, and
the Tamron has very high field curvature at the wide end.
The Pentax is really the only choice in this range, at least for me.

As long as we are adding to the list, I should contribute. Like I said, I can easily see why some people choose the Pentax. However, I can easily see why people choose the Tamron too. We could go on for a long time adding to the list.

For example, the heavy barrel distortion (3.55%) which accompanies the wide angle of the Pentax vs the moderate distortion (2.7%) which comes with the wide angle of the Tamron. There is a big price to pay for this 1mm.

Tamron handles CAs better.

Wide open the TAMRON IS EXCELLENT--(why else buy an f 2.8 lens)

The corner performance of the Tamron is perhaps its most dominant hold over the Da.

Tamron focuses closer; Tamron has better max magnification

The Tamron is lighter

The Tamron costs a lot less

A good copy is more likely to come from the Tamron line

[OrenMc]

Opps You slipped that in while I was still typing.

I agree the Tamron has a lot of pros but since I have had this in my hands I have been out in weather I normally wouldn't venture with my Tamron. I really love how quiet it is also.

But I am a pixel peeper and this is the hard decision.

[Jewelltrail]

OrenMc
Okay. I am not very good at testing but this is a couple shots I took today. I thought I was past the BF/FF issue but it looks like the qiuck test I did earlier was too quick.

First shot is without any adjustments. The focus was on the buckle on the belt between the airtanks and hose connections around it waist.

I just looked, carefully, at the 2 images at full size from your Flicker link. I do not notice a difference in focusing accuracy. I do notice that the first image has a slight glare, due to a different lighting than the 2nd image. I think this, more than anything else, accounts for the difference seen. Just my HO.

[EricT]

As long as we are adding to the list, I should contribute. Like I said, I can easily see why some people choose the Pentax. However, I can easily see why people choose the Tamron too. We could go on for a long time adding to the list.

For example, the heavy barrel distortion (3.55%) which accompanies the wide angle of the Pentax vs the moderate distortion (2.7%) which comes with the wide angle of the Tamron. There is a big price to pay for this 1mm.

Tamron handles CAs better.

Wide open the TAMRON IS EXCELLENT--(why else buy an f 2.8 lens)

The corner performance of the Tamron is perhaps its most dominant hold over the Da.

Tamron focuses closer; Tamron has better max magnification

The Tamron is lighter

The Tamron costs a lot less

A good copy is more likely to come from the Tamron line

Of course the Tamron is a very good lens, and has some advantages over the 16-50mm as well. I just wanted to explain to aweir why someone might choose the latter.
Also, just out of interest, has someone measured the barrel distortion at 17mm for the Pentax? It's probably slightly lower than at 16mm.

[Jewelltrail]

Orenc: I agree the Tamron has a lot of pros but since I have had this in my hands I have been out in weather I normally wouldn't venture with my Tamron. I really love how quiet it is also.

My Tamron accompanies me in weather like this, with temperatures well below zero--Fahrenheit. For example:
https://www.pentaxforums.com/forums/post-your-photos/45963-winter-hike.html

PS: Winds above treeline sometimes gusting in excess of 40mph: I could not hear the Tamron focusing.

[OrenMc]

I see the glare also but I had the camera on a tripod and it was only a couple seconds between shots. I didn't change anything other than focus adjustment.
Because of the focus shift I think there would be these type of factors. ie. the glare.
But this is the reason I am asking questions because I really am quessing on a lot of this.

BTW I used to be an avid hiker also and plan to get back into it. It was the outdoors that started me in photography. Thanks fror the link to your thread. Oh to be back in the hills!!

I just looked, carefully, at the 2 images at full size from your Flicker link. I do not notice a difference in focusing accuracy. I do notice that the first image has a slight glare, due to a different lighting than the 2nd image. I think this, more than anything else, accounts for the difference seen. Just my HO.

[Jewelltrail]

EricT:Of course the Tamron is a very good lens, and has some advantages over the 16-50mm as well. I just wanted to explain to aweir why someone might choose the latter.
Also, just out of interest, has someone measured the barrel distortion at 17mm for the Pentax? It's probably slightly lower than at 16mm.

Eric, most of the test reports that I see only give the distortion for the extreme wide end. But I would be willing to bet the Pentax has less distortion @ 17mm than @ 16--for sure. The fact is, both lenses mostly clear up of distortions as you approach 24mm.

Both lenses are excellent! The differences we are discussing are not something we are going to see in pictures for the most part. I just thought my $$ were better spent with the Tamron, and respect the fact that other people feel their $$ are better spent with the Pentax. if money was not an option for me, I would probably have taken the Pentax and rested easier on my Winter hikes.


And I just am here to explain the Tamron choice--in the same manner you wish to explain the Pentax choice.

[OrenMc]

It is probably the distortion that I am seeing also of course so I thank you for pointing that out.
A lot of this is just a case of LBA and the idea of owning a Pentax * lens.

We have a little break in the weather with some patches of blue so I am going to take advantage of that. Wish me luck.

[Jewelltrail]

OrenMc: I see the glare also but I had the camera on a tripod and it was only a couple seconds between shots. I didn't change anything other than focus adjustment.

I don't know about you, but I find it virtually impossible to control lighting in outdoor settings for these kinds of tests.

OrenMc:It is probably the distortion that I am seeing also of course so I thank you for pointing that out.

Are you being serious? No distortion at this focal length. The distortion is found at the extreme wide end. Does the Flicker account strip EXIF data? I think someone here said something about this once. I do not know what you are seeing, but the lens looks great on my end. with or without the focus adjustment.

I think a lot of the criticism both of these lenses receive, like so many other lenses, is from expectations which are too high by the owners.