Go Back   Steve's Digicams Forums >

LinkBack Thread Tools Search this Thread
Old Mar 20, 2008, 2:48 PM   #11
Senior Member
mtngal's Avatar
Join Date: Nov 2005
Location: Frazier Park, CA
Posts: 16,177

JimC - interesting about the Sony version of Tamron's 18-250 lens. Pentax has their version of the same lens, but the only thing I can find out that's different is the glass coatings. I'm not convinced that would be worth payingapremiumfor since Tamron's coatings now are quite good (the Pentax version is more expensive). It sounds like the Sony version would be worth the extra cost.

There are people on another forum that have posted pictures taken with the K200, but I don't know anyone here who has one. They look good so far, but haven't paid enough attention to draw any conclusions yet (like I have for the K20, which is a significant improvement over the K10).
mtngal is offline   Reply With Quote
Old Mar 20, 2008, 3:01 PM   #12
JimC's Avatar
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378

Different coatings can get you in trouble from time to time.

Sony does the same thing with some of the Tamron designs (for example, Sony uses different coatings for their versions of the Tamron 28-75mm f/2.8, Tamron 18-200mm and Tamron 18-250mm).

I got in trouble switching from a Tamron SP 35-105mm f/2.8 AF lens to a Minolta 100mm f/2 AF lens not long ago shooting a basketball game with my Sony A700. I set a custom white balance using the Tamron (which has slightly warmer colors), and switched to the Minolta later (which has more neutral colors).

As a result, there was a big difference in the images with the same custom white balance set. Fortunately, I was shooting raw + jpeg. So, it shouldn't be too hard to fix. Unfortunately, I've already processed them once using Bibble on my wife's laptop (which had the LCD set way too bright), and the photos look underexposed on my CRT. So, I'll have to do them over again using my desktop when I get a chance. :-)

I know Minolta worked very hard to make sure their better quality lenses all had the same color transmission characteristics. So, that kind of thing could be important to some shooters, and I can imagine that Pentax, Canon, Nikon and others may do the same thing with some of their better lenses.

Note: edited lens models above (I had the Tamron lens specs wrong)
JimC is offline   Reply With Quote
Old Mar 20, 2008, 3:20 PM   #13
Senior Member
mtngal's Avatar
Join Date: Nov 2005
Location: Frazier Park, CA
Posts: 16,177

My first thought when I was reading your post was that I hoped you were shooting raw!

You are right, though, that under certain conditions the coatings can be very important. I have a version of a Pentax Takumar 135mm 2.5 lens that came with my Pentax ME camera in 1980. At the time Pentax used the "Takumar" name for their K-mount uncoated lenses. My lens has the same sharpness as a Pentax SMC 135mm 2.5 lens but the current resale value of it is about $30 or less, compared to over $100 for the coated lens. One only has to use mine under side/backlighting conditions to see why the difference in value (mine is very subject to flare with a digital camera - it wasn't much of a problem when I was shooting film).

In this particular case, though, and as far as Pentax versus Tamron versions of this lens, I just don't think it makes much difference.
mtngal is offline   Reply With Quote
Old Mar 21, 2008, 1:35 AM   #14
Senior Member
interested_observer's Avatar
Join Date: Jul 2006
Location: Tumbleweed, Arizona
Posts: 1,381

I read your post the other day and obviously the information so far is spot on. I just wanted to add a couple of items that has not been touched on yet.

During the day, I think that your going to want the 300mm focal length to get the on coming plane. I do not think that the autofocus speed will be critical as the depth of field at f16+ will be from 1,000 feet to infinity. A zoom lens would give you probably the greatest flexability. The one item of concern, and Jim would probably be the expert here is the autofocus - not in terms of speed, but contrast on the cross section, for locking on the target. I say this because you might not have sufficient contrast to lock, even though the focus should be on infinite, you might hunt longer than necessary. Switching to Manual focus would solve this, but it would be one more step.

During the night, I would think that your targets of interest would essentially double. You would probably want to use more of the zoom range, but potentially needing to go to the opposit focal lengths - 18 to 40mm to frame landscapes. With the darkness and the speed of the plane, you going to be faced with longer exposure times, so that is where your faster lenses, or higher ISO speeds (or both) will come into play. The all in one lens will be at its worst performance here. The 2 lens set may fair better in this respect, but then you have the lens change and storage to contend with. Also, the faster lenses are larger and heaver (and more expensive).

I know that Pentax has a 18-55 kit lens that is extremely good. They also have a new lens out, the 55 - 300. Pairing these two together would cover just about everything.

The other thought is burst. In that most of the images your taking will be things moving, I would probably just set it on multiple images and burn off 2 to 3 images at a time.

Also, I do think that the coatings would be important for some other reasons. With flying your going to be probably taking a lot of varying sun shots (sun sets, sun rises, sun & clouds, etc.) and this is probably where the coatings will help you the best.

Hope that helps - and enjoy!
interested_observer is offline   Reply With Quote
Old Apr 13, 2008, 3:01 PM   #15
Junior Member
ullal's Avatar
Join Date: Jan 2008
Posts: 3

I just finished reading the review for the Sony A350 at imaging resource (IR) and was wondering how the Pentax K200D would compare on the following points:

1) Autofocus Speed - above average according to IR for the A350

2) Focus Tracking - below average according to IR for the A350

3) Shot to shot time in single shot mode (most important feature for me)

ullal is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -5. The time now is 4:25 AM.