Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
05-03-2011, 05:09 AM   #31
Veteran Member
selar's Avatar

Join Date: Jul 2007
Location: Sydney, Australia
Photos: Gallery | Albums
Posts: 2,035
Would be interesting if you shot the same with the A135 @ 2.8. Thats the GPO at Martin Place.

05-03-2011, 07:01 AM   #32
Veteran Member
rparmar's Avatar

Join Date: Jan 2008
Photos: Gallery
Posts: 8,783
QuoteOriginally posted by Christine Tham Quote
After the disappointing results I reported on my DA*50-135mm wide open, the good news from running my tests is that I now know my A135mm is very sharp wide open at f2.8.
Coming late to this thread, but am interested as I have been shooting at 135mm lately.

With all respect I do not find the examples you posted that sharp. Acceptable, yes. Maybe better than my own old M42 lens. But nothing like "razor sharp". If your zoom is actually worse than this there must be some problem with it.

This illustrates how useless subjective phrases like "very sharp" are. One person's sharp is another's acceptable.
05-03-2011, 07:13 AM   #33
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
QuoteOriginally posted by excanonfd Quote
Christina used a set methodology to test her lenses exactly the same so as to minimize the random factors - as we all probably were taught in HS Chemistry - to say these things can be pretty random is to imply her tests are meaningless.
Not at all - just that the effect of camera shake when dealing with such long exposures is very difficult to control.

Anyhow, it's no skin off my back if anyone wants to take those samples as sufficient proof. But if it were me, I'd be in a hurry to repeat them to at least account for the effect I mentioned - the very clear and obvious difference in the specular highlights from f/2.8 to f/4.
05-03-2011, 01:33 PM   #34
Veteran Member
Christine Tham's Avatar

Join Date: Nov 2008
Location: Sydney, Australia
Photos: Gallery
Posts: 2,269
Original Poster
QuoteOriginally posted by selar Quote
Would be interesting if you shot the same with the A135 @ 2.8. Thats the GPO at Martin Place.
Well, maybe we can meet up and take photos at exactly the same spot and compare?

I can even bring a Leica along? (seriously, I took some photos on an M9 two weeks ago, and the Summarit makes my Pentax primes look soft).

05-03-2011, 01:40 PM   #35
Veteran Member
Christine Tham's Avatar

Join Date: Nov 2008
Location: Sydney, Australia
Photos: Gallery
Posts: 2,269
Original Poster
QuoteOriginally posted by rparmar Quote

With all respect I do not find the examples you posted that sharp.
With all due respect, it is completely impossible to judge sharpness looking at photos that have been reduced to 700 pixels wide.

If you read my post carefully, I was commenting on the fact that I had recently conducted some tests of lens resolution across all the lenses I used frequently, and I was pleasantly surprised by the results of the A135mm at f2.8 that I went out to take some photos which I think turned out rather "nice."

I wasn't asking people to judge sharpness from 700 pixel wide compressed photos uploaded to Facebook. But thanks for trying.
05-03-2011, 02:01 PM   #36
Veteran Member
Christine Tham's Avatar

Join Date: Nov 2008
Location: Sydney, Australia
Photos: Gallery
Posts: 2,269
Original Poster
QuoteOriginally posted by Marc Sabatella Quote
But if it were me, I'd be in a hurry to repeat them to at least account for the effect I mentioned
Hey Marc, I think you missed reading this from a earlier post I made in this thread:

QuoteOriginally posted by Christine Tham Quote
And I tried with a second DA* supplied by Pentax Australia and achieved the same results.

I even took several versions of the DA* shots to absolutely convince myself I was not doing something wrong.
05-03-2011, 02:47 PM - 1 Like   #37
Veteran Member
rparmar's Avatar

Join Date: Jan 2008
Photos: Gallery
Posts: 8,783
QuoteOriginally posted by Christine Tham Quote
With all due respect, it is completely impossible to judge sharpness looking at photos that have been reduced to 700 pixels wide.
So why post them in a thread about lens sharpness? That seems rather misleading.

QuoteOriginally posted by Christine Tham Quote
I wasn't asking people to judge sharpness from 700 pixel wide compressed photos uploaded to Facebook. But thanks for trying.
With an attitude like that I wish you all the best getting help with your "problem". Since you have difficulty presenting the correct context and then interpreting the results of same, I apparently need to be especially explicit. So, let make this really easy for you.

Even for web images those are not that sharp.

Next!
05-03-2011, 03:02 PM   #38
Veteran Member
Christine Tham's Avatar

Join Date: Nov 2008
Location: Sydney, Australia
Photos: Gallery
Posts: 2,269
Original Poster
QuoteOriginally posted by rparmar Quote
So why post them in a thread about lens sharpness?
Uhmm, the thread isn't about lens sharpness.

Some people (not me) chose to hijack the thread to talk about the sharpness (of a completely different lens, not the one featured in the original post).

05-03-2011, 04:02 PM   #39
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
QuoteOriginally posted by Christine Tham Quote
Hey Marc, I think you missed reading this from a earlier post I made in this thread:
I saw that post; what I didn't see were the images themselves.
05-03-2011, 04:06 PM   #40
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
QuoteOriginally posted by Christine Tham Quote
Uhmm, the thread isn't about lens sharpness.
From the very first paragraph of the very post:

QuoteQuote:
After the disappointing results I reported on my DA*50-135mm wide open, the good news from running my tests is that I now know my A135mm is very sharp wide open at f2.8.
You made the comparison yourself; we're just commenting on it.
05-03-2011, 04:54 PM   #41
Veteran Member
Christine Tham's Avatar

Join Date: Nov 2008
Location: Sydney, Australia
Photos: Gallery
Posts: 2,269
Original Poster
QuoteOriginally posted by Marc Sabatella Quote
I saw that post; what I didn't see were the images themselves.
I didn't see any point posting multiple images that are fundamentally identical. The images are quite large. I am truly sorry that you distrust me so much as to insist on them.

QuoteOriginally posted by Marc Sabatella Quote
You made the comparison yourself; we're just commenting on it.
If you reread what I wrote, it wasn't a comparison, but a rationale for me to use the lens, and to practice my manual focusing abilities. There's no explicit or implicit comparison to the DA* intended in the original post, for all I know using the DA* may have resulted in more or less the same images (or perhaps even better - since I'll be able to use auto focus).

As I recall, you were the one who wanted to see a comparison. I am truly sorry I tried to be helpful, and allow the thread to be hijacked by a discussion I really wasn't interested in, and not the original purpose of the thread.
05-03-2011, 09:15 PM   #42
Veteran Member




Join Date: Mar 2009
Location: Midwest
Photos: Gallery
Posts: 1,407
QuoteOriginally posted by Christine Tham Quote
As I recall, you were the one who wanted to see a comparison. I am truly sorry I tried to be helpful, and allow the thread to be hijacked by a discussion I really wasn't interested in, and not the original purpose of the thread.
I don't think it's really fair to call it 'hijacking' a thread when someone comments on your observations; to suggest responses are off-topic would be to imply your original statement itself was off-topic, which seems rather... counter-intuitive.

QuoteQuote:
After the disappointing results I reported on my DA*50-135mm wide open, the good news from running my tests is that I now know my A135mm is very sharp wide open at f2.8.
I'm not certain at all how it can be reasonable asserted that this statement *isn't* about sharpness. If that wasn't what you intended, a simple "Oh, sorry, I didn't mean to make this about lens sharpness - just look at the pictures" would have re-oriented the discussion, I think.
05-03-2011, 10:00 PM   #43
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
QuoteOriginally posted by Christine Tham Quote
I am truly sorry that you distrust me so much as to insist on them.
It's not a question of trusting you - it's nothing that personal. It's very difficult to conduct well-controlled tests. I should know; I've messed up plenty myself. But along the way, I've learned what some of the red flags tend to be, and I'm just expressing my honest opinion that I see some of those red flags here. Do with that information as you will.
05-03-2011, 10:09 PM   #44
Veteran Member




Join Date: Jun 2009
Location: on the wall
Photos: Gallery
Posts: 715
I use an M135f3.5 and I'm not surprised that your A135 is sharp.
05-03-2011, 11:31 PM   #45
Veteran Member
selar's Avatar

Join Date: Jul 2007
Location: Sydney, Australia
Photos: Gallery | Albums
Posts: 2,035
QuoteOriginally posted by dragonfly Quote
I use an M135f3.5 and I'm not surprised that your A135 is sharp.
Different lens formula. The A135/2.8 is rumored to be based on a Takumar Bayonet version. We all know what the Takumar bayonets were good for.
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!
f2.8, ferry, friend, k-mount, pentax lens, photos, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Nature Some wide open Tulips JeffJS Post Your Photos! 6 04-18-2010 07:37 AM
Landscape Wide Open Garden rustynail925 Post Your Photos! 2 03-09-2010 08:22 AM
77/1.8 wide open... igor Post Your Photos! 14 08-17-2009 05:36 AM
F- 50mm 1.7 Wide Open bwield Post Your Photos! 2 07-08-2009 12:46 PM
DA* 55mm 1.4 wide open samples!!! Nice Steelski Pentax SLR Lens Discussion 2 02-16-2009 04:27 AM



All times are GMT -7. The time now is 09:22 PM. | 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