Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
07-11-2012, 05:55 PM   #76
Veteran Member
Docrwm's Avatar

Join Date: Sep 2010
Location: Somewhere in the Southern US
Photos: Gallery | Albums
Posts: 11,275


Someone I respect pointed out to me that a review of this magnitude and the effort it took deserves our respect. I agree unreservedly and do respect the time and effort the review took. My concern is that it went to press with what appears to be a dud lens, instead of redoing it with another copy of the lens.

The new review has some serious problems with it IMHO. The 40Ltd copy seems to either be a bum copy or there was a user error in the focus tests because the results do not match any reports over the years of that lenses performance. Also, the ratings used seem to be set up to over emphasize "build quality" and under emphasize actual performance as a lens. The entire "Features" section or the "Build Quality" section needs to go, or somehow be deemphasized. Frankly, for a lens to receive a 5, yes the 40Ltd got a five, in Sharpness and then go on to beat the other two lenses indicates something fundamentally wrong with the whole process.

The Ratings and scores for each:
DA 35mm f/2.4 = 7.5
DA 40mm f/2.8 Limited = 8.1
DA 40mm f/2.8 XS = 7.8

35/2.4
Sharpness 8
Distortion 9
Bokeh 7
Aberrations 7
Autofocus 8
Build Quality 6
Features 5
Value 10
Overall 7.5 (Good)

40Ltd
Sharpness 5
Distortion 9
Bokeh 8
Aberrations 9
Autofocus 9
Build Quality 10
Features 8
Value 7
Overall 8.1 (Very Good)

40XS
Sharpness 8
Distortion 9
Bokeh 9
Aberrations 7
Autofocus 9
Build Quality 7
Features 5
Value 8
Overall 7.8 (Good)

If you eliminate the "Features" rating you see that the 40Ltd and 40XS get precisely the same scores, however in the critical Sharpness category the 40XS out performs the 40LTD dramatically (an 8 vs. a 5).
35/2.4 = 7.86
40Ltd = 8.14
40XS = 8.14

Perhaps a "do over" with a different copy of the 40Ltd is called for in this case?



Last edited by Docrwm; 07-11-2012 at 06:12 PM.
07-11-2012, 06:02 PM   #77
Pentaxian
normhead's Avatar

Join Date: Jun 2007
Location: Near Algonquin Park
Photos: Gallery | Albums
Posts: 25,824
QuoteQuote:
The 50mm keeps the world as you see it with your eyes, but a 35mm, even if on crop, will still feel "wide angle"-ish in terms of space compression and distortion.
The actual number is about 43 mm for your eye. A 35 and a 50 are equidistant in different directions but both pretty close. The 40 however should be pretty much bang on.
07-12-2012, 07:09 AM   #78
Moderator
Site Supporter
Blue's Avatar

Join Date: Jun 2008
Location: Florida Hill Country
Photos: Gallery | Albums
Posts: 17,212
QuoteOriginally posted by lytrytyr Quote
You'd have to search the online retailers or auction sites.

However, if you don't find hoods that size,
you might be able to get a step-up ring
to get you to a size (like 37mm) where it's easy to find hoods.
Another option would be to use a 27mm step-down ring if one is available as a hood. It would work similar to the DA 40 ltd hood. This is the type of setup I have on my F 28/2.8
07-12-2012, 07:38 AM   #79
Pentaxian




Join Date: Nov 2011
Photos: Gallery | Albums
Posts: 3,735
QuoteOriginally posted by Blue Quote
Another option would be to use a 27mm step-down ring if one is available as a hood. It would work similar to the DA 40 ltd hood. This is the type of setup I have on my F 28/2.8
That might risk vignetting, since the DA 40 XS is already an APS-C lens
(although the DA 40 Ltd does reportably work with its hood on FF:
SMC Pentax-DA 40mm F2.8 Limited Reviews - DA Prime Lenses - Pentax Lens Reviews & Lens Database)

07-12-2012, 07:54 AM   #80
Moderator
Site Supporter
Blue's Avatar

Join Date: Jun 2008
Location: Florida Hill Country
Photos: Gallery | Albums
Posts: 17,212
QuoteOriginally posted by lytrytyr Quote
That might risk vignetting, since the DA 40 XS is already an APS-C lens
(although the DA 40 Ltd does reportably work with its hood on FF:
SMC Pentax-DA 40mm F2.8 Limited Reviews - DA Prime Lenses - Pentax Lens Reviews & Lens Database)
I use the F 28/2.8 on aps-c and 135. The hood from the DA 40 worked on my F 28 as well. You would just have to figure out how far to step it down. There is a thread on here regarding this method of hoods.
07-12-2012, 01:18 PM   #81
Veteran Member
Anvh's Avatar

Join Date: Sep 2011
Posts: 4,616
QuoteOriginally posted by civiletti Quote
Not a depth of field scale to be found on these three. It's a shame how craft has been discounted - prices, not so much.
It only appears that way, if you look at the lenses that had a scale it where mostly all prime with the exception of some zoom the extended in a way that you could mark the barrel.
Since we use less primes these days it appears like that.
07-12-2012, 01:23 PM   #82
Veteran Member
Anvh's Avatar

Join Date: Sep 2011
Posts: 4,616
Step down ring is not a effectief hood though, you want something longer.
You could get a step up ring to 49mm and use the DA40 limited hood but that's an expensive option.
07-12-2012, 06:25 PM   #83
Moderator
Site Supporter
Blue's Avatar

Join Date: Jun 2008
Location: Florida Hill Country
Photos: Gallery | Albums
Posts: 17,212
QuoteOriginally posted by Anvh Quote
Step down ring is not a effectief hood though, you want something longer.
You could get a step up ring to 49mm and use the DA40 limited hood but that's an expensive option.
Have you ever looked at the hood on the 21 ltd or 40 ltd? The 21 is flat and rectangular (mounts via bayonet) and the 40 has a taper down conical one. Several of us have successfully used 49 to 28mm step down rings on the F 28/2.8 lens.


Last edited by Blue; 07-12-2012 at 06:30 PM.
07-12-2012, 11:34 PM   #84
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
QuoteOriginally posted by Anvh Quote
Nope that excuse won't work, he is the conversation.
I can't tell what you are talking about. I made at least a dozen different points in the post you quoted, and then the other posta you cited each contain dozens more points. I can't tell which specific point you are not understanding, or which specific two points you think are in comflict, or what "excuse" you mean. I can only assume you are trying to tell me something about the context of the remarks you previously suggested were in conflict, but I've already explained how they are *not* in conflict and would only appear to be in co flict if you misundertood one of my setences. So I have no idea what you are saying here.

QuoteQuote:
Anyway basically what it comes down what i'm saying is that the difference between linear perspective of the camera and the viewer is what creates the effect of perspective disorder.
I *think* I understand what you are trying to say, but you are using the terms a but incorrectly if so. The camera has no linear perspecitve, nor does the viewer. Linear perspective is a function of position, as I think we both agree. So what I think - or at least hope - you are trying to say is that the perspective distortion effect is caused by the difference between the linear perspective *that exists within the printed image because of the position it was shot from* and the *linear perspective the viewer of the printed image is mislead into expecting the image to depict*. In which case, that would be a true statement. And the only missing element would then be, answering the question of what *causes* the viewer to be mislead about what linear perspective to expect. And the answer is, the viewer is mislead because the angle of view of the image depicted does not match the angle subtended by the print from the viewing position. This causes the viewer to misjudge the distance to the scene, and this in turn causes him to misinterpet the linear perspective.

Stated simly, it is not the fact that a telephoto picture is taken from a distance that causes a viewer of the resulting image to be mislead about the linear perspective. It is the narrow AOV, resulting in the subject being rendered large in the frame, that fools the viewer into thinking the photographer was closer to the subject than he actually was. The same scene shot from the same distance with a nirmal lens would render the subject smaller, thus giving the viewer the necessary visual cue as to distance from subject that is required to form proper expectations for liner perspective.


QuoteQuote:
We take as standard that the viewer is standing away a typical distance but if you know that isn't the case and know the distance viewers stand and the print size you can actually calculate what the normal lens will be right?
Yes. My understanding is the IMAX uses this concept. By employing a larger than normal screen for the viewing distance, they create a scenario in which a wide angle lens becomes normal.

QuoteQuote:
Besides telephoto is about the construction/formula of a long focus lens
True. I am using the term rather more colloquially here: any lens that creates a narrow than normal AOV can be consider telephoto for the purpose of discussions like this, regardless of whether they are truly telephoto in internal construction. If it bothers someone to use the word this way, feel free to substitute another word to mean this.
07-17-2012, 01:54 PM   #85
Senior Member




Join Date: Apr 2010
Location: Austin, TX
Photos: Albums
Posts: 152
Is the lack of a lens hood a problem for the DA35/2.4, in terms of image contrast? I know it doesn't come with a lens hood, and I doubt there's any convenient easy to attach lens hood options.
- Sheldon
07-17-2012, 02:06 PM   #86
Veteran Member
Docrwm's Avatar

Join Date: Sep 2010
Location: Somewhere in the Southern US
Photos: Gallery | Albums
Posts: 11,275
QuoteOriginally posted by sheld Quote
Is the lack of a lens hood a problem for the DA35/2.4, in terms of image contrast? I know it doesn't come with a lens hood, and I doubt there's any convenient easy to attach lens hood options.
- Sheldon
I love the lens, but it benefits from a hood. There are rubber 3-stage hoods that I rather like on my lenses that cost very little and are threaded to take filters. But, there is no threading for a bayonet hood if that is what you meant.
07-18-2012, 01:40 PM   #87
Veteran Member
Anvh's Avatar

Join Date: Sep 2011
Posts: 4,616
QuoteOriginally posted by Blue Quote
Have you ever looked at the hood on the 21 ltd or 40 ltd? The 21 is flat and rectangular (mounts via bayonet) and the 40 has a taper down conical one. Several of us have successfully used 49 to 28mm step down rings on the F 28/2.8 lens.
I've the 40mm ltd so yes i've
Anyway i talked about effectiveness of a hood and the hood of the 40 ltd is more effective then a step down ring, reason is simple.
The hole of both is about the same size because the hood of the ltd extend more forward it's more effective blocking the incoming rays.
I said nothing about the 21mm

Here this might help.
Lens hoods

Last edited by Anvh; 07-18-2012 at 01:59 PM.
07-18-2012, 01:55 PM   #88
Veteran Member
Anvh's Avatar

Join Date: Sep 2011
Posts: 4,616
@ Marc.
I'm glad you are also lost what it is about and that's just the point

Just a different way of saying it, thanks for the explanation.

we are very agreeable these days, its amazing =]

Well the comments are quite technical so correct use of words is a good idea right and it was just a side point about the telephoto lens nothing negative, thought you might found that fact interesting =]
07-19-2012, 02:33 PM   #89
Moderator
Site Supporter
Blue's Avatar

Join Date: Jun 2008
Location: Florida Hill Country
Photos: Gallery | Albums
Posts: 17,212
QuoteOriginally posted by Anvh Quote
I've the 40mm ltd so yes i've
Anyway i talked about effectiveness of a hood and the hood of the 40 ltd is more effective then a step down ring, reason is simple.
The hole of both is about the same size because the hood of the ltd extend more forward it's more effective blocking the incoming rays.
You completely missed the point. I suggested a step down ring as a hood for the DA 40mm XS and I cited how some of us used that method on the F 28/2.8 with good success. The DA 40mm LTD comes with a very cool hood so your point is moot. It was used as a concept for a step down ring.

QuoteOriginally posted by Anvh Quote
I said nothing about the 21mm
No, but I did because the DA 21 LTD goes, it has a flat hood with a rectangular opening that attaches via a bayonet system which allows the mounting of small filters inside the hood.

QuoteOriginally posted by Anvh Quote
Here this might help.
Lens hoods
We weren't discussing what they are and how they work. However, I am glad to hear you learned something about hoods.

Last edited by Blue; 07-19-2012 at 02:45 PM.
07-19-2012, 02:47 PM   #90
Pentaxian
Na Horuk's Avatar

Join Date: Feb 2012
Location: Slovenia, probably
Photos: Gallery | Albums
Posts: 10,863
You can find 27mm filters (UV, even polarizers) and hoods online. The 27mm is not that uncommon for camcorders apparently.
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!
40mm, cost, k-mount, lenses, ltd, pentax lens, quality, slr lens, xs
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Voigtlander Ultron 40mm f/2 vs. Pentax 40mm Ltd (warning: amateur test) dasuhu Pentax SLR Lens Discussion 48 12-05-2013 08:34 AM
DA 40mm F2.8 Limited or DA 35mm f/2.4 AL .... rrwilliams64 Pentax SLR Lens Discussion 14 07-14-2011 11:40 AM
DA 40mm 2.8 Ltd vs DA (L) 35mm 2.4 Metalwizards Pentax SLR Lens Discussion 19 02-14-2011 09:36 AM
DAL 35mm 2.4 vs. DA 40mm 2.8 LTD paperbag846 Pentax SLR Lens Discussion 51 10-30-2010 12:50 AM



All times are GMT -7. The time now is 08:22 PM. | 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