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Forum: Pentax DSLR Discussion 02-23-2017, 11:31 PM  
Do you use a lens hood, polarizer or both?
Posted By ak_kiwi
Replies: 16
Views: 1,779
If you use a rubber fold out hood that screws into the polariser you can use both.
Forum: Pentax SLR Lens Discussion 02-17-2016, 05:38 PM  
DA* 70-200mm images at Dpreview..
Posted By ak_kiwi
Replies: 15
Views: 1,995
"As an added bonus, and to our delight, we found the 70mm F2.4's image circle covers full-frame, so we snapped some samples with it as well."
Forum: Post Your Photos! 03-01-2015, 07:18 PM  
Macro Bug !
Posted By ak_kiwi
Replies: 9
Views: 789
Oh I hear what you are saying and I very much subscribe to the "If one is getting the required results then the method must be correct" type of thinking :)
And indeed the results you are getting prove the actual statement quoted below from the photozone test is quite wrong -
"MTF (resolution)
Typical for most macro lenses the Sigma AF 105mm f/2.8 EX DG macro performed great in the MTF lab. The lens is already excellent in the center at wide-open aperture with marginally worse corners. The peak performance is reached at around f/5.6 with an excellent center and border quality. As usual diffraction is the limiting factor at smaller aperture settings. Extremely small apertures such as f/32 should be avoided due to very pronounced softness. The tested sample showed a slightly uneven resolution distribution.
"

Look forward to your next article on light!

Stopping (down) now :)
Chris
Forum: Post Your Photos! 02-26-2015, 12:07 AM  
Macro Bug !
Posted By ak_kiwi
Replies: 9
Views: 789
Ok - now you've got me interested. I don't know if the below chart relates to the same lense you are using (I know the camera isn't) but as a very rough guide the chart makes it look likes like diffraction is an issue at f32?

From Photozone (the HSM variant has a similar fall off)
Forum: Lens Clubs 02-25-2015, 11:31 PM  
F* & FA* club!
Posted By ak_kiwi
Replies: 821
Views: 163,718
Very nice shot Stavri.
Here is my attempt with same combo :)
(Just love this old glass)
Forum: Travel, Events, and Groups 02-25-2015, 10:07 PM  
2015 Pentax Forums T-Shirt Design Contest
Posted By ak_kiwi
Replies: 367
Views: 55,943
And, shock horror,;) everywhere else in the world too actually :lol:
Forum: Post Your Photos! 02-25-2015, 09:57 PM  
Macro Bug !
Posted By ak_kiwi
Replies: 9
Views: 789
Another set of great photos!
Question for you old4570 - Is that stop of f32 correct? If so, I'm trying to get my head around why the images are so sharp :confused:
Forum: Pentax News and Rumors 02-22-2015, 12:15 PM  
DPReview gives a nod to the Pentax FF
Posted By ak_kiwi
Replies: 124
Views: 13,852
Wow! :confused:
Forum: Pentax News and Rumors 02-21-2015, 01:02 PM  
DPReview gives a nod to the Pentax FF
Posted By ak_kiwi
Replies: 124
Views: 13,852
Cheer up! :) Look on the bright side and as Class A reported - He mentioned Pentax as a manufacturer of "photographer's cameras" with "well-positioned controls".
Forum: Pentax SLR Lens Discussion 02-21-2015, 12:30 PM  
Pentax 12-24 or 20-40 (choice down to two)
Posted By ak_kiwi
Replies: 43
Views: 4,042
Just to throw something else into the mix - how about the Sigma 17-70mm F2.8-4 DC Macro HSM ? IMHO it is a versatile walk around lens that has good IQ and profiles are available in Lightroom. Remember to price in the USB lens dock in order to get the absolute best out of this lens.
Forum: Pentax Price Watch 02-19-2015, 10:30 PM  
Big savings on Pentax lenses (USA)
Posted By ak_kiwi
Replies: 27
Views: 5,448
yup - proven in this no bs test.














You Tube



Forum: Pentax Price Watch 02-19-2015, 02:49 PM  
Big savings on Pentax lenses (USA)
Posted By ak_kiwi
Replies: 27
Views: 5,448
FWIW there is a slight difference on sealing with DA*, which used to be called 'AW', which is claimed superior to 'WR'.
This white paper explains it
Forum: Pentax SLR Lens Discussion 02-18-2015, 07:22 PM  
D FA* 70-200 and D FA 150 - 450 samples
Posted By ak_kiwi
Replies: 54
Views: 7,859
But the area in focus is sharp......... :D
Forum: Pentax SLR Lens Discussion 02-18-2015, 11:33 AM  
D FA* 70-200 and D FA 150 - 450 samples
Posted By ak_kiwi
Replies: 54
Views: 7,859
As mentioned in a previous post & thread there seems to be something up with the 150-450 front and back out of focus areas.
Do any optical engineers have an insight to what this is ?
Forum: Troubleshooting and Beginner Help 02-16-2015, 11:10 AM  
Is my lens in focus?-sample shots included
Posted By ak_kiwi
Replies: 21
Views: 2,568
I would suggest you do a methodical focus test with a proper focus target (see my post #15 in this thread).
It would be beneficial to re-post in a new thread with your results so answers can be directed to your particular circumstance.
Forum: Troubleshooting and Beginner Help 02-15-2015, 10:39 AM  
Is my lens in focus?-sample shots included
Posted By ak_kiwi
Replies: 21
Views: 2,568
One of the things I too found with my K3, when compared to the K-5 series cameras, was it really showed up small errors in focusing. After many hours shooting my trusty old focus target (and cat dogs and kids etc) I came to the conclusion that the targets I was using were just not good enough to give repeatable accurate results. I found it was imperative to have a focus target parallel to the sensor plane - and the ability to confirm this parallel was critical to developing accurate evaluations of tests. In the end I purchased a LensAlign focus target which in about 5 minutes told me what I needed to know to fix the problem.

However,just before you buy a LensAlign - try one of these targets on a repeatably well lit wall. Square off the camera to the wall and make sure it is on center with the target also. Test your close auto focus Vs further away auto focus by comparing with shots using live view (with focus peaking) and manual focus.
If you want to get real keen arrange 4 more targets to mark out the corners of the frame. This will give you a check on possible decentering and replaces the "newspaper check" method.
Forum: Troubleshooting and Beginner Help 02-14-2015, 03:05 PM  
Is my lens in focus?-sample shots included
Posted By ak_kiwi
Replies: 21
Views: 2,568
See this link to give you an idea show where you should be focusing for a shot such as you posted.

---------- Post added 15-02-15 at 11:29 AM ----------



If you get a noticeable difference the lense may be defective but I don't think that is the problem.



You should be focusing (corrected info from other post)on a point 5.6 meters from the camera (camera sensor plane to be exact) to get everything from 3 meters to infinity in acceptable focus.
Forum: Troubleshooting and Beginner Help 02-14-2015, 02:24 PM  
Is my lens in focus?-sample shots included
Posted By ak_kiwi
Replies: 21
Views: 2,568
Good point MadMathMind.
ychousa - here is the Photozone resolution graph for the DA 35 f2.4 (on a K-5) if you havn't seen it. (I guessed the lense based on the exif and CA on the focus test - but don't worry about the CA since my 31 Ltd does the same thing)
Forum: Troubleshooting and Beginner Help 02-14-2015, 02:06 PM  
Is my lens in focus?-sample shots included
Posted By ak_kiwi
Replies: 21
Views: 2,568
Focus adjustment looks pretty good to me going by the top and bottom edges of the 14mm mark. You could also check for possible de-centering by shooting a sheet of newspaper parallel to the sensor plane and comparing edges/corners.
The photo you posted may be soft on the left hand side because your focus point is too far into the scene. For the f11 used I came up with a hyperfocal distance of 7.35m 5.6m giving a near limit of about 6.54 3m and infinity.
Do you have a link to the full size file of this shot?
Forum: Pentax Price Watch 02-11-2015, 11:34 AM  
New Pentax O-GPS1 $127.
Posted By ak_kiwi
Replies: 20
Views: 2,382
I don't think the new camera for FFF ( Full Frame Fanatics - of which I am a member) would be "off" at all since it must be 1.5 times better :D
Forum: Pentax Price Watch 02-06-2015, 07:18 PM  
New Pentax O-GPS1 $127.
Posted By ak_kiwi
Replies: 20
Views: 2,382
yes :)
Forum: Pentax Lens Articles 02-05-2015, 01:26 PM  
DA lenses on Full Frame: Test Shots thread
Posted By ak_kiwi
Replies: 511
Views: 361,075
From the Ricoh press release on the FF to come -
"Compatible with DA-series interchangeable lenses, using an image-cropping function"
Forum: Pentax News and Rumors 02-05-2015, 12:15 PM  
HD PENTAX-D FA 150-450mm F4.5-5.6ED DC AW
Posted By ak_kiwi
Replies: 1,426
Views: 219,153
So what are the shortcomings you found when actually using the DA18-135 DC focus motor? IMHO thought it was very fast and accurate on the K-5 series and K3 bodies. Why would this DC focus system not perform just as great with the new 150 -450? :confused:
(And yes I know that asahi man and others have reported that the 150-450 uses a different , and presumably even better, form of this DC focus system)
Forum: General Photography 02-04-2015, 11:58 AM  
Tired of getting burnt
Posted By ak_kiwi
Replies: 22
Views: 1,707
Sounds like you should return it for a full refund.

FWIW I had a camera shop sell a lense, on behalf for me, that it was 3 years old, in very good condition with mint box and all paperwork.
The camera shop sold it as a "new lense that was old stock" which I thought was stretching the truth somewhat.
Forum: Pentax News and Rumors 02-04-2015, 10:32 AM  
HD PENTAX-D FA 150-450mm F4.5-5.6ED DC AW
Posted By ak_kiwi
Replies: 1,426
Views: 219,153
Which is not a bad thing is it?
But one would have to compare features such as AW/WR, in-body compatible features and actual personal requirements before deciding if the comparison is balanced.
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