Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
10-07-2009, 11:48 AM   #46
Veteran Member




Join Date: Mar 2007
Location: Toronto (for now)
Posts: 1,749
QuoteOriginally posted by Crepusculum Quote
All the shots were taken with the same settings.
You are going to be crucified for this test, you need to use M mode as using Av the camera easily freaks out and meters wrong .... you can see the kit lens is severely under exposed.

Looks like the polariser is your enemy!

10-07-2009, 11:56 AM   #47
Junior Member




Join Date: Sep 2009
Location: Tucson, AZ
Posts: 46
Original Poster
I called Pentax to talk about what I was seeing. The gentleman wasn't that helpful and said he did not think there was an issue. then when I mentioned that I had posted my results on a forum he seemed to lose as respect in my opinion at all.
10-07-2009, 11:58 AM   #48
Junior Member




Join Date: Sep 2009
Location: Tucson, AZ
Posts: 46
Original Poster
QuoteOriginally posted by Alfisti Quote
You are going to be crucified for this test, you need to use M mode as using Av the camera easily freaks out and meters wrong .... you can see the kit lens is severely under exposed.

Looks like the polariser is your enemy!
You are correct I will run another test right now.
10-07-2009, 12:14 PM   #49
Veteran Member




Join Date: Mar 2007
Location: Toronto (for now)
Posts: 1,749
QuoteOriginally posted by Crepusculum Quote
I called Pentax to talk about what I was seeing.
I'd call Larry King to discuss pentax lenses before calling Pentax themselves ... you'd get a more intelligent answer.

10-07-2009, 12:17 PM   #50
Senior Member
mk07138's Avatar

Join Date: Mar 2008
Location: Frostburg Maryland
Photos: Gallery | Albums
Posts: 151
I really think that your first test identified the problem. I think that your polarizer is defective. As for the different exposures I've always had different lenses that expose differently when using auto settings. Seeing as how your original problem was related to blurry soft images and not exposure I'd focus more on that than the fact that your kit lens underexposes compared to the DA* when using AV.
10-07-2009, 12:29 PM   #51
Veteran Member
vizjerei's Avatar

Join Date: May 2007
Location: Toronto
Photos: Gallery
Posts: 1,418
QuoteQuote:
If you look at the quality of the DA* vs. DA, it is very hard for me to notice much a difference in quality of the picture, but the DA* does take a slight edge, but it's not as much as I thought it would.
The selling point of DA* 16-50 is the larger aperture and weatherseal, when you step down to f8, most of the lens preform quite good for sure (if not you should just throw it away )
10-07-2009, 12:30 PM   #52
Junior Member




Join Date: Sep 2009
Location: Tucson, AZ
Posts: 46
Original Poster
Ok I took some more shots, because I was concerned that the DA* was not 'that' much better then the kit lens. These I did in manual mode (as was suggested). Wireless 3 second delay shots.

Manual Mode. 1/1250 sec @ F/5.6. ISO 200. Spot Metering.

DA* 16-50mm



!00%



DA 18-55mm



100%




It seems that the DA lens is still underexposing a bit. The quality of each shot is still not far off from each other, to the point that if I was shooting stepped down I don't think it would make a difference in which lens I choose. This is a bit dis-concerning due to the price of the DA* vs the DA. But at least that is my opinion on my unscientific test (as the Pentax rep told me).
10-07-2009, 12:33 PM   #53
Junior Member




Join Date: Sep 2009
Location: Tucson, AZ
Posts: 46
Original Poster
QuoteOriginally posted by mk07138 Quote
I really think that your first test identified the problem. I think that your polarizer is defective. AV.
I agree with you. I might just stick to my high end B&W from now on.

10-07-2009, 12:34 PM   #54
Veteran Member




Join Date: Mar 2007
Location: Toronto (for now)
Posts: 1,749
At f/8, honestly there is bugger all difference between $100 and $1,000 lenses. The differences would be subtle in rendering, colour, contrast and fine detail as well as edge sharpness.

This is why i do not own fast zooms, the penalty in weight and size is not worth it to me.
10-07-2009, 12:52 PM   #55
Veteran Member
Pentaxor's Avatar

Join Date: May 2009
Location: Vancouver, B.C.
Photos: Gallery
Posts: 6,513
the polarizer made the IQ look bad. aside from the different exposure and meter reading, there is also significant difference between the DA* and the DA kit lens IQ, I don't know if you noticed it but the DA* has more depth and contrast detail at higher apertures, and therefore is more sharper than the DA kit lens which is a bit soft, but not bad at all for a kit lens.
10-07-2009, 01:28 PM   #56
Ash
Community Manager
Loyal Site Supporter
Ash's Avatar

Join Date: Mar 2007
Location: Toowoomba, Queensland
Photos: Gallery | Albums
Posts: 22,678
QuoteOriginally posted by Alfisti Quote
At f/8, honestly there is bugger all difference between $100 and $1,000 lenses. The differences would be subtle in rendering, colour, contrast and fine detail as well as edge sharpness.

This is why i do not own fast zooms, the penalty in weight and size is not worth it to me.
Fast zooms however are designed to perform well at large apertures.
The kit lens does not do all that well at 50mm at f/5.6, but the 16-50 does - and hence the application of the 16-50 is much broader and more versatile.

One who does not use the lens in these conditions may indeed be wasting money and their backs!
10-07-2009, 02:41 PM   #57
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
My read:

- You've definitely proved the polarizer is the main problem.

- You've proved the kit lens does quite well, and like Alfisti and for the same reasons, I don't consider fast zooms worth the price or weight. The kit lens is fine when I want zoom, but I prefer smaller/lighter/cheaper primes when I want speed or I think I can eek out just a little more IQ.

- I wouldn't sweat the difference in exposure between the two lenses in Av mode. For one thing, you were metering slightly different scenes (one lens has had a wider view than the other), so you really had no reaosn to expect an identical exposure. In particualr, the differen amounts of the sky and white vehicle visble certainly affected the meter. And for another, you were pretty right at the border between clpping and not clipping, so the camera had a tough choice to make. I'd actually call the DA* shot dangerously close to being overexposed, but this is all subjective. If you consistently saw the camera choosing a full stop darker exposure on the same scene in Av mode, that would be worth noting, but that's not goign to be the case.

- When using M mode, there was barely any difference in exposure. If the DA* produced a *slightly* brighter image, most likely that's simply showing it uses better glass with a higher light transmission. There, the DA* just earned a bit of its price premium.
10-07-2009, 03:45 PM   #58
Veteran Member
Ben_Edict's Avatar

Join Date: Jul 2007
Location: SouthWest "Regio"
Photos: Albums
Posts: 3,303
QuoteOriginally posted by Crepusculum Quote
All the shots were taken with the same settings.
If I follow the notes you provided, the DA* shot was exposed f/5.6 - 1/800s whereas the much darker 18-55 image was exposed with f/5.6 - 1/1600s, one stop faster - which explains the darker image and the good contrast. This makes the contrast look better and narrows the visible gap between the humble kit lens and the DA*. You can reduce the influence of perception by getting the expsoure with both lenses to the same level.

What is also very clear in your image (and I have rarely seen such a bad example), is the negative influence of the polarizer you used.

Ben
10-08-2009, 12:11 AM   #59
Junior Member




Join Date: Sep 2009
Location: Tucson, AZ
Posts: 46
Original Poster
I have been thinking about going the prime route for a bit. It is just such a hassel to sell the 16-50 and my 60-250. Not to mention that it really would not save me any money to get the primes as the ones I was looking at are quite expensive too.
10-08-2009, 08:24 AM   #60
Veteran Member
Pentaxor's Avatar

Join Date: May 2009
Location: Vancouver, B.C.
Photos: Gallery
Posts: 6,513
QuoteOriginally posted by Crepusculum Quote
I have been thinking about going the prime route for a bit. It is just such a hassel to sell the 16-50 and my 60-250. Not to mention that it really would not save me any money to get the primes as the ones I was looking at are quite expensive too.
you're not getting the FA LTD's are you? just in case, the DA LTD's (21,35,40,70) are quite a cheaper alternative but great as well. get an FA 50 1.4 or the DA50 macro which are also very nice. and may I recommend an FA/DFA 100 macro for telephoto, I like these two because they are really have a very high IQ. 14mm is also affordable. that would leave you a DA* 200 for the longer telephoto. hope this helps.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
image, k-mount, pentax lens, reduction, shake, shots, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
some horrible luck here irishwhite Pentax Film SLR Discussion 2 09-04-2010 03:34 PM
Horrible Dust on my K-x sensor gut1kor Troubleshooting and Beginner Help 7 07-24-2010 07:06 PM
So horrible at ISO800 henryjing Pentax DSLR Discussion 42 04-17-2010 10:26 AM
Detroit's Beautiful, Horrible Decline deadwolfbones General Talk 37 09-26-2009 07:54 AM
My horrible LBA... Vulpix Pentax SLR Lens Discussion 4 03-07-2007 07:53 AM



All times are GMT -7. The time now is 03:34 AM. | See also: NikonForums.com, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top