Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
02-07-2010, 07:43 PM   #16
Veteran Member
Laurentiu Cristofor's Avatar

Join Date: Nov 2009
Location: WA
Photos: Albums
Posts: 3,044
QuoteOriginally posted by Wheatfield Quote
Pretty much any lens at f/8.
I wish that were true.

02-07-2010, 07:52 PM   #17
Veteran Member




Join Date: Nov 2008
Location: The Untied States
Photos: Albums
Posts: 1,882
QuoteOriginally posted by Laurentiu Cristofor Quote
I wish that were true.
With which lenses isn't it?
02-08-2010, 10:52 PM   #18
Veteran Member
Laurentiu Cristofor's Avatar

Join Date: Nov 2009
Location: WA
Photos: Albums
Posts: 3,044
QuoteOriginally posted by wallyb Quote
With which lenses isn't it?
There's a difference between a lens being at its sharpest and a lens being sharp.

If you want more specific examples, check this link - you can compare more lenses there. The comparator tool on that site is also very helpful to give an idea about the difference that can be expected between zoom and prime lenses.
02-08-2010, 11:34 PM   #19
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
QuoteOriginally posted by Laurentiu Cristofor Quote
There's a difference between a lens being at its sharpest and a lens being sharp.
True, but sharp is a relative term, and the differences are usually pretty small at those apertures. Read the OP's description of the standard of sharpness, and let us know which lenses you think wouldn't fit the bill.

02-09-2010, 12:02 AM   #20
Veteran Member
wlachan's Avatar

Join Date: Sep 2006
Location: Canada
Photos: Albums
Posts: 2,626
QuoteOriginally posted by Laurentiu Cristofor Quote
There's a difference between a lens being at its sharpest and a lens being sharp.
True, not that everyone cares though. The DA16-45/4 I had was pretty horrible at the long end against the FA43 in any situations. One would think it was sharp until you have seen something so significantly sharper.
02-09-2010, 12:14 AM   #21
Veteran Member
PentaxPoke's Avatar

Join Date: Jan 2008
Location: Oklahoma
Posts: 1,411
FA35 is one of the sharpest Pentax lenses ever. At f/4 it is sharper than most lenses at f/8. It is even sharper than some Limiteds, and sharper than the Pentax 100mm macros.

Considering the price of the FA35, I can't imagine a lens with a better sharpness/cost ratio.
02-09-2010, 12:32 AM   #22
Veteran Member
Jewelltrail's Avatar

Join Date: May 2008
Location: Rhode Island
Photos: Albums
Posts: 4,180
QuoteQuote:
EliotK: What lens would produce tack-sharp images for the obsessed pixel-peeper at a reasonable price? (under $500-600?) This is indoor/studio detailed photography but NOT macro, shot from approximately 3-12 ft distance on a tripod.

Thank you.
QuoteQuote:
EliotK:EliotK It is product studio photography, off a tripod, focal distance probably 35-75mm, shot from about 3-10ft, but has to be sharp so that later when customer reviews images they can zoom into parts of image reasonably tight without heavy blur.
Thanks everyone.
Certainly, the primes which have been suggested thus far, which fit between your desired focal range 35-75mm, would all fit the bill. but, if you want some of the freedom which a zoom provides. while still maintaining sharpness, for below your $500 budget, the Tamron 28-75mm would do nicely--I'm sure.
02-09-2010, 02:03 AM   #23
Veteran Member
Jimfear's Avatar

Join Date: Apr 2007
Location: Uppsala, Sweden
Photos: Gallery
Posts: 576
QuoteOriginally posted by PentaxPoke Quote
Considering the price of the FA35, I can't imagine a lens with a better sharpness/cost ratio.

K35/3.5? I have no idea how the FA35 handles compared to the K35 but it sure is a lot more expensive.

02-09-2010, 10:13 AM   #24
Veteran Member
Laurentiu Cristofor's Avatar

Join Date: Nov 2009
Location: WA
Photos: Albums
Posts: 3,044
QuoteOriginally posted by Marc Sabatella Quote
Read the OP's description of the standard of sharpness, and let us know which lenses you think wouldn't fit the bill.
What makes you think I didn't? Let's read it together once again:

QuoteOriginally posted by EliotK Quote
What lens would produce tack-sharp images for the obsessed pixel-peeper at a reasonable price?
"tack-sharp images for the obsessed pixel-peeper" - this sounds like someone willing to split hairs. Kit zooms, for example, wouldn't fit that bill (18-55, 50-200). Of course, your sharpest lens will be the epitome of sharpness until you get to see what a sharper lens can produce.

Also, even if it were true that lenses were undistinguishable at f/8 (which it isn't, and you can get more examples by comparing lenses on the site I pointed to in my previous post), it would be impractical to give away use of wider apertures. Check that Canon 300mm lens at f/2.8 and f/8 and it's amazing how sharp it is even wide open - that is what a sharp lens is about.
02-09-2010, 10:44 AM   #25
Forum Member




Join Date: Nov 2009
Posts: 70
My 18-55, for example, while pretty good at F8, was still not nearly as sharp as my sharpest lenses, which have been the Sigma 70 f2.8 macro and the DA 35 f2.8 macro.
02-09-2010, 10:45 AM   #26
Veteran Member




Join Date: Nov 2008
Location: The Untied States
Photos: Albums
Posts: 1,882
QuoteOriginally posted by Laurentiu Cristofor Quote
Also, even if it were true that lenses were undistinguishable at f/8 (which it isn't, and you can get more examples by comparing lenses on the site I pointed to in my previous post), it would be impractical to give away use of wider apertures. Check that Canon 300mm lens at f/2.8 and f/8 and it's amazing how sharp it is even wide open - that is what a sharp lens is about.
And that's the absolute opposite of the OP's other request, "at a reasonable price". We're not saying all lenses are equally sharp at f/8, like there's some sharpness percentage that all lenses achieve. We're saying that around f/8 just about any lens tends to outresolve the sensor. This is true of even the kit lens. However, we're talking strictly about resolution. There are other lens aberrations that may be present no matter how stopped down a lens is, such as coma, CA, LCA, poor contrast/microcontrast, and distortion. This is where more expensive lenses show their chops better than cheaper ones. But as far as having high sharpness, just about any lens will at f8 to f/11 or so.

If the OP wants to make it easy on himself, just get a macro lens like the Sigma 50, 70, Tamron 90, or Pentax 100/3.5. All fairly reasonably priced (usually below $350).
02-09-2010, 10:12 PM   #27
Veteran Member
Laurentiu Cristofor's Avatar

Join Date: Nov 2009
Location: WA
Photos: Albums
Posts: 3,044
QuoteOriginally posted by wallyb Quote
And that's the absolute opposite of the OP's other request, "at a reasonable price".
You're making a strawman argument here. I recommended the Nokton for a lens within the OP's budget. The Canon is just an example of what it means for a lens to be tack sharp - I've used that site because it makes it easier to see the differences that can exist between lenses.

The Nokton would be sharper than most non-macro lenses within the OP budget, maybe even sharper than some macros, so all lenses are not equal, even within a budget, even at f/8.

QuoteOriginally posted by wallyb Quote
We're not saying all lenses are equally sharp at f/8, like there's some sharpness percentage that all lenses achieve. We're saying that around f/8 just about any lens tends to outresolve the sensor.
If lenses would usually outresolve sensors, then most of them would be off the chart in their photozone tests (which still use the K10D camera, whose resolution is at the low end today for an SLR). Yet, this does not happen and there's marked difference between them at any aperture you wish to compare.

QuoteOriginally posted by wallyb Quote
But as far as having high sharpness, just about any lens will at f8 to f/11 or so.
Not true. Here are some 100% crops from some shots I took at some resolution charts some months ago when I felt like testing lens resolution. They are all shots taken with lenses that are well within the OP budget - the kit lenses and some older primes. Leaving aside the aberrations, the primes look sharper than the zooms, even at f/8. The prime shots even manage to capture the paper texture, which is pretty much lost in the zoom shots.



Dead-center, you're right, the difference is much smaller, but just move a bit from the center - not really border territory, and the difference becomes way more visible. These crops are from the center of the left half of the frame. Hope this helps.
02-10-2010, 12:46 AM   #28
Veteran Member




Join Date: Jan 2009
Location: Canada
Posts: 1,255
QuoteOriginally posted by Laurentiu Cristofor Quote


Dead-center, you're right, the difference is much smaller, but just move a bit from the center - not really border territory, and the difference becomes way more visible
Note that a magenta tint would indicate a slight front focus. Green would indicate back focus.
02-10-2010, 02:17 AM   #29
Veteran Member
Laurentiu Cristofor's Avatar

Join Date: Nov 2009
Location: WA
Photos: Albums
Posts: 3,044
QuoteOriginally posted by asdf Quote
Note that a magenta tint would indicate a slight front focus. Green would indicate back focus.
I know what you're saying, but in this case, I think these show that the focal plane is actually curved.

These are all manual focus shots using LiveView at top magnification for focusing. The tripod was not moved between shots at same focal length, I just took the camera off to exchange lenses. I checked all shots and if they didn't look sharp, I tried a couple more times and I kept the sharpest. Zooms consistently exhibited softness off-center.

For all these shots there is no obvious tint in the center of the frame (which is where I focused on) - the tint starts showing as you look farther away from the center.

DA18-55@40 has some magenta tint towards center - I can't really notice any green.

M40 has a very slight green edge towards exterior, and even harder to notice magenta towards center. Hard to even notice these in that crop.

DA55-200@200 works on reverse - it has green towards interior and magenta towards the exterior of the frame.

K200 is like DA - green interior, magenta exterior

Because the tint is symmetric with respect to the center, I think this is because the focal plane is curved for most of these lenses. The M40 looks the best, but then again - that's a design derived from the Zeiss Tessar.

Here are 100% center crops from the same shots as above:



It's interesting to notice that in the center, the DA50-200 comes up as better than the K200. Otherwise, the M40 is a clear winner. As I said before, the difference is much smaller in the center - it's towards the outside of the shot that softness can be noticed more clearly.

And here is a new set of left and right crops showing the symmetric tint (they correspond to the same lenses as before):



The zooms seem to exhibit a much larger variation in sharpness across the frame.

And for the final bonus, some crops that show that mirror lenses don't have such bad resolution - these are the results I got from the Tokina 500mm - shot from quite a way from the target:



Not bad for resolution and pretty much no aberrations.
02-10-2010, 02:25 AM   #30
Veteran Member
Laurentiu Cristofor's Avatar

Join Date: Nov 2009
Location: WA
Photos: Albums
Posts: 3,044
Actually, on second thought, I don't think the tint is due to a curved focal plane - must be just CA.
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!
k-mount, lens, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
K-7 video mode and sharpening for pixel-peepers richtrav Pentax DSLR Discussion 0 08-19-2009 12:28 AM
For you pixel peepers... wildman Pentax SLR Lens Discussion 12 01-27-2009 10:33 PM
K200D Noise Performance Chart - Pixel Peepers Rejoice! cputeq Pentax DSLR Discussion 8 06-01-2008 07:04 PM
Wanted! Pixel Peepers - new Sigma 17-70mm superfuzzy Pentax SLR Lens Discussion 9 01-15-2008 07:39 PM
Hay pixel peepers-Help regken Photographic Technique 1 12-02-2007 11:30 AM



All times are GMT -7. The time now is 03:15 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