Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
12-10-2010, 11:12 AM   #16
New Member




Join Date: Jul 2008
Location: Portola Valley, CA
Posts: 13
Second brand-new sample of Pentax-D FA 55mm f/2.8 has same hazing and scratch-like marks
diglloyd.com blog: December 2010

I'll leave open the possibility (claimed by Pentax) that visible haze and visible scratch-like marks somehow, magically, have zero impact on image quality, especially with the sun in the frame.

But if this brand-new lens were a used lens, I'd not want to see those faults! It's simple: I expect to see crystal clear optics with any lens. A few dust specs are normal, even in new lenses. But if this 55/2.8 build is acceptable, then any visual inspection of a lens is pointless as I've never even seen a used lens look this bad. It's the haze especially that bugs me.

I also received a used Pentax-A 75mm SMC 75/2.8 (for $159!), and it has crystal clear glass, and no scratch-like marks.

12-10-2010, 11:14 AM   #17
New Member




Join Date: Jul 2008
Location: Portola Valley, CA
Posts: 13
QuoteOriginally posted by Thomas Quote
On a positive note: it appears Pentax is not attempting to influence the test results by cherry-picking a particularly good sample to be sent to you.
to Thomas: Pentax is not sending me these lenses, in fact they refused to loan anything at all.

I bought and paid for them at B&H. They are brand new. I now have two samples of the 55/2.8.
12-10-2010, 11:15 AM   #18
New Member




Join Date: Jul 2008
Location: Portola Valley, CA
Posts: 13
I should clarify: As I still have not received the Pentax 645D, I can’t make any pictures with either lens just yet.

But what will it show? Two hazy lenses are both going to produce lower contrast (if I can see it, then the sensor sees it), so there is no reference lens at 55mm that would allow demonstrative proof or disproof that the hazing is a non-issue.
12-10-2010, 01:05 PM   #19
Forum Member
Tim Wilson's Avatar

Join Date: Nov 2010
Location: Chicago
Posts: 54
Disconcerting. One of those is on it's way to me, also from B&H, quite possibly from the same batch.

Tim

12-10-2010, 08:19 PM   #20
New Member




Join Date: Jul 2008
Location: Portola Valley, CA
Posts: 13
QuoteOriginally posted by Tim Wilson Quote
Disconcerting. One of those is on it's way to me, also from B&H, quite possibly from the same batch.

Tim
If you have a *low* power laser, that's probably the best way to check out the lens for imperfections

I used an 1800 lumen Lupine Betty headlamp, and it might be better at showing haze.

Be sure to check out at various angles, from the rear seems easiest to see. Use a reference lens if you have one. Some dust specs are normal in even new lenses; the haze I'm talking about is uniform.
12-16-2010, 03:54 PM   #21
New Member




Join Date: Jul 2008
Location: Portola Valley, CA
Posts: 13
Just posted portions of my review of the 645D, along with some examples. Much more coming.

diglloyd.com blog: December 2010
12-16-2010, 03:55 PM   #22
New Member




Join Date: Jul 2008
Location: Portola Valley, CA
Posts: 13
From what I see, the issues I noted with the 55/2.8 do not seem to impair image quality — very good news.

Also, the 55/2.8 looks to be a very good performer.
12-16-2010, 09:04 PM   #23
Senior Member




Join Date: Nov 2010
Location: Calgary, Alberta
Posts: 270
I just picked up a new 55 f/2.8 this evening. It doesn't look particularly hazy, but the innermost surface of the rear elements does have a bunch of circular looking marks quite clearly visible with a 200 lumen light. They're punctuated by stronger arcing lines that may or may not be scratches, often intersecting a speck of what I presume is either polishing grit or some contaminant from the final polish; definitely not just "dust". Doesn't look nearly as good as the rear glass of older FA or A lenses I have. Unfortunately not too different from what Lloyd has reported.

I will make some photographs with the lens and see how the results look, they might be okay as Lloyd has found with his. I do like the size, weight and weather sealing of the 55, and the improved AF mechanism should be welcome. But perhaps this polish situation isn't quite the standard Pentax wants to set with the new line of SDM lenses...

12-18-2010, 04:46 PM   #24
Senior Member




Join Date: Nov 2010
Location: Calgary, Alberta
Posts: 270
Out of curiosity, I ended up taking my 55 f/2.8 back into my local dealer to examine it against another 55 they had there. The one they had was worse on the inner surface of the rear elements... quite a bit more dust / grit, and the same kind of circular scratches or smears. It also seemed a bit hazy. The guys there thought these effects didn't look good, so I returned mine even though I hadn't yet done any serious shooting with it. We'll see if a new shipment brings any improvement...
01-16-2011, 07:43 PM   #25
New Member




Join Date: Jul 2008
Location: Portola Valley, CA
Posts: 13
Added the following to my Pentax 645D review:

Pentax-A 200mm f/4 on the Pentax 645D.

Pentax FA 80-160mm f/4.5 @ 80mm on the Pentax 645D.

Pentax FA 80-160mm f/4.5 @ 120mm on the Pentax 645D.

comparison of Pentax-A 150mm f/3.5 versus Pentax FA 80-160mm f/4.5.

test of the Pentax 67 55mm f/4 on the Pentax 645D.

test of the Pentax 67 300mm f/4 on the Pentax 645D.

blur from the Pentax 645D shutter at low shutter speeds.

See:
diglloyd.com blog: January 2011
01-16-2011, 08:43 PM   #26
Site Supporter




Join Date: Dec 2010
Location: Colorado Front Range
Photos: Gallery | Albums
Posts: 181
I've been lending lenses...

... and watching for digilloyd's results. Day by day, they're getting better. This camera appears to have a learning curve for focusing manual lenses, and he's still ascending it. One of my lenses, the 200/4, is turning out to look much better than when first tested, because he achieved better focus with it the sceond time.

What will it take to make focusing easier and more consistent, short of a firmware upgrade (for greater magnification upon review) or a hardware improvement (LV)? Is anyone finding focusing magnifiers helpful? Laser rangefinders? Tape measures? Eyecups? I think the old Large Eyecup is a wonderful design that can't help but help anyone focus the P645, so I'm sending him one to add to the testing.

Lloyd is laps ahead of any other net source in testing the P645 with legacy lenses, so let's all hit his site early and often!
01-16-2011, 08:52 PM   #27
Site Supporter




Join Date: Dec 2010
Location: Colorado Front Range
Photos: Gallery | Albums
Posts: 181
Well, I said I was sending him a Large Eyecup. But I have no idea how to remove it from my camera! It seems attached very firmly. Does anyone know the trick?
01-16-2011, 09:37 PM   #28
Forum Member




Join Date: Jan 2011
Location: Tokyo
Posts: 83
I'm considering getting a Brightscreen20/20 and surely an Accurfocus (Brightscreen Accurfocus Magnifier) - I have both for Mamiya RZ and it helps v. much. I do though have concerns about screen replacement on the 645D with metering and AF, not to mention screens themselves being a hit or miss affair in my experience.

QuoteOriginally posted by Wheatridger Quote
... What will it take to make focusing easier and more consistent, short of a firmware upgrade (for greater magnification upon review) or a hardware improvement (LV)? Is anyone finding focusing magnifiers helpful? Laser rangefinders? Tape measures? Eyecups? I think the old Large Eyecup is a wonderful design that can't help but help anyone focus the P645, so I'm sending him one to add to the testing.
Vise Grips and X-Acto knife ?

QuoteOriginally posted by Wheatridger Quote
Well, I said I was sending him a Large Eyecup. But I have no idea how to remove it from my camera! It seems attached very firmly. Does anyone know the trick?

Last edited by VoltMan; 01-16-2011 at 09:43 PM.
01-16-2011, 10:26 PM   #29
Site Supporter




Join Date: Dec 2010
Location: Colorado Front Range
Photos: Gallery | Albums
Posts: 181
I want it to be a non-destructive removal, for camera and eyecup. I like them both! There must be some secret handshake that makes it easy...
01-16-2011, 11:36 PM   #30
Site Supporter
Dougg's Avatar

Join Date: Jan 2011
Location: Central Washington
Photos: Albums
Posts: 251
What's in the Box


Pentax 645D Digital SLR Camera (Body)
  • AC PLUG CORD D-CO2U
  • PENTAX USB CABLE I-USB107
  • RECHARGEABLE L-ION BATTERY D-LI90 (B)
  • BATTERY CHARGER D-BC90 (A)
  • PENTAX STRAP O-ST107
  • PENTAX LARGE EYE CUP O-EC107 <-----------------------
  • PENTAX STRAP O-ST53
  • 1-Year Limited Warranty
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!
645d, camera, diglloyd, fa, lens, lenses, lloyd, medium format, p67, site, time
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
645D - delay in testing Ed Hurst Pentax Medium Format 1 07-27-2010 01:14 AM
Need help with lens testing methods JohnBee Pentax SLR Lens Discussion 4 12-24-2009 09:29 AM
Lens Testing Target jon.partsch Pentax SLR Lens Discussion 3 10-28-2009 12:56 PM
Testing new lens slowpez Post Your Photos! 5 02-19-2009 03:16 PM
On Lens Testing (Or, Is This 50mm Lens Any Good?) carpents Pentax SLR Lens Discussion 18 06-21-2007 05:45 AM



All times are GMT -7. The time now is 12:16 AM. | See also: NikonForums.com, CanonForums.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