Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
07-17-2009, 07:29 AM   #1
Site Supporter
Site Supporter




Join Date: Jul 2009
Photos: Gallery
Posts: 24
IR (Infrared)friendly pentax lenses?

First of all Hello to all. I'm new here.

Is there a list of IR (Infrared)friendly pentax lenses online, all I can find is canon stuff?

This is for an IR modified K10D with 680nm pass filter internally installed. I just ordered the camera.

I have these pentax lenses (and a tamron) and I was wondering which of ones of these is the least prone to hot spots.

I usually shoot wide so I was hoping that at least one of my wide lenses is ok for this

Pentax DA 12-24mm

DA Limited 21mm

FA Limited 43mm

Pentax DA 16-45

Pentax DA* 50-135

Tamron 90 (prime)

Pentax DA 55-300

Pentax DA*300mm

Thanks for any help
frank


Last edited by digitaldaydreams; 07-17-2009 at 07:40 AM.
07-17-2009, 08:25 AM   #2
Veteran Member
Duck Dodgers's Avatar

Join Date: Dec 2007
Location: in the 24½th Century!
Photos: Gallery
Posts: 439
First, welcome to the forums!

Second, and maybe I'm missing something here, but why wouldn't any lens be IR-friendly? Even the old ones had IR focus-compensation lines.
07-17-2009, 09:12 AM   #3
Site Supporter
Site Supporter




Join Date: Jul 2009
Photos: Gallery
Posts: 24
Original Poster
RE:why wouldn't any lens be IR-friendly?

not sure why but,

it's my understanding after looking at various IR sites that
some lenses produce a hot spot (bright spot) in the picture, ruining the photo.
some lenses don't do that.

I was hoping that some IR shooten pentaxians would know the where abouts of a lens list for IR friendly pentax lenses and see if any of my lenses listed at the beginning of my post are going to work out for me.

I have a pretty good lens assortment and bought an IR modded pentax k10d becuase I already have pentax lenses and figured that 1 or 2 would work well with IR

Last edited by digitaldaydreams; 07-17-2009 at 09:14 AM. Reason: further explaination
07-17-2009, 09:40 AM   #4
Pentaxian
ivoire's Avatar

Join Date: Mar 2007
Location: chicago burbs
Photos: Gallery
Posts: 3,369
I can't answer the question but I'd like to know where you got the modified K10 and if more are available

07-17-2009, 10:38 AM   #5
Veteran Member
creampuff's Avatar

Join Date: May 2007
Location: Singapore
Photos: Gallery
Posts: 3,955
The term IR-friendly relates to the issue of hot-spotting, whereby digital IR images shot with certain camera lenses exhibit noticeable bright or uneven exposure, typically in the center of the IR image.
The degree of hot-spotting does vary with the aperture in use, so even if a lens does show mild hot spots, it can sometimes be managed by using a wider aperture when shooting.
The IR focusing mark found on many legacy lenses is to compensate for the shorter wavelength compared to the visible spectrum when shooting infrared sensitive film, which is quite different compared to digital IR photography. Cameras that have been converted to IR-only use also need to have their AF tweaked in order to compensate for the shift in wavelength. Stopping down a lens to increase DOF can mask slight focus errors if the camera's AF has not been tweaked.

There was an earlier thread listing out whether some lenses exhibited hot-spotting here:
https://www.pentaxforums.com/forums/general-photography-techniques-styles/364...ed-bodies.html

Pass - No hot spots

DA 14mm
DA 15mm Limited
DA 17-70mm SDM
DA 18-55mm
DA 18-55mm II
DA 18-55mm WR
DA 18-250mm / Tamron 18-250mm
DA 21mm
FA 20-35mm
FA 28mm
FA 28-70mm f/4
FA 28-200mm
A 35mm f/2, DA 35mm f/2.8 Macro Limited
FA 50mm f/1.4, FA 50mm f/1.7, A 50mm f/1.4, A 50mmf/1.7, A 50mm f/2
DA 70mm
FA 77mm Limited
FA 135mm
DA* 300mm / FA 300mm
DA 50-200mm, DA 50-200mm WR
DA 55-300mm, DAL 55-300mm
Sigma 28mm f/2.8 (manual focus)
Sigma 50mm f/2.8 (manual focus)
Sigma 17-70mm f/2.8~4.5
Lensbaby II

Fail - Clear or varying degree of hot spots

DA 12-24mm (slight, when stopped down in bright conditions)
DA 16-45mm (clear irregular hotspot)
DA* 50-135mm (slight)
FA 50mm Macro (slight, noticeable when stopped down)
DFA 50mm Macro (very slight up to f/4, worsens when stopped, better than FA 50mm macro)
DA* 55mm (visible)
FA 100mm Macro f/2.8 (very slight)
Sigma 10-20mm (visible, depends on scene)

The trend is many modern zooms and macro lenses don't fare particularly well.

Last edited by creampuff; 01-01-2012 at 11:36 AM. Reason: updated listing
07-17-2009, 10:40 AM   #6
Site Supporter
Site Supporter




Join Date: Jul 2009
Photos: Gallery
Posts: 24
Original Poster
RE: where I got my modded k10d

search ebay for converted pentax he is the only one showing an ir pentax ( k100 i think)

you can email him about a k10
07-17-2009, 10:46 AM   #7
Site Supporter
Site Supporter




Join Date: Jul 2009
Photos: Gallery
Posts: 24
Original Poster
Thanks creampuff, nailed it, exactly what i was looking for.
12-23-2011, 09:29 AM   #8
Loyal Site Supporter
Loyal Site Supporter
blackcloudbrew's Avatar

Join Date: Mar 2009
Location: Cotati, California USA
Photos: Gallery | Albums
Posts: 3,816
Please add the DA*55 to the hot spot list.

07-31-2014, 07:32 AM   #9
Senior Member




Join Date: May 2014
Posts: 115
Pentax smc-A 28mm f2.8 - Hotspot with Filter.
Any 3d party lenses lists?
07-31-2014, 08:17 AM   #10
Pentaxian
Not a Number's Avatar

Join Date: Mar 2012
Location: Venice, CA
Posts: 4,301
Note: precisioncamera in CT will do IR conversions. It appears precisioncamera will be the main service center for Ricoh/Pentax.

Lens Hotspot Performance Database | Kolari Vision Infrared
10-12-2014, 02:00 PM   #11
New Member
clayhaus's Avatar

Join Date: Aug 2008
Location: Salt Lake City, UT
Posts: 6
IR conversion of Pentax

Spencer's Cameras in Alpine Utah will also IR-convert just about any camera.
10-03-2016, 02:15 AM   #12
Site Supporter
Loyal Site Supporter
gordon_l34's Avatar

Join Date: Sep 2008
Location: Brisbane, Australia
Photos: Gallery | Albums
Posts: 516
QuoteOriginally posted by ivoire Quote
I can't answer the question but I'd like to know where you got the modified K10 and if more are available
Hi,
I have a K-m that has been converted to infrared for sale if you are interested.
Regards.
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!
da, ir, k-mount, lenses, pentax, pentax lens, slr lens, tamron
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Lenses usable for infrared photography? Noisychip Pentax SLR Lens Discussion 36 02-25-2012 07:12 AM
pentax k-x infrared intervalometer, anyone tried this one? Thanatos Pentax DSLR Discussion 8 10-28-2010 06:46 AM
Pentax Electronic Cable Switch v/s Pentax Infrared Remote Control F brosen Pentax DSLR Discussion 9 10-26-2009 05:08 AM
Pentax 18-55 vs 18-55II for infrared barondla Pentax SLR Lens Discussion 2 04-06-2008 08:36 AM
Using infrared with a Pentax K110D pookey83 Photographic Technique 3 10-09-2007 01:10 PM



All times are GMT -7. The time now is 08:01 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