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Forum: Troubleshooting and Beginner Help 06-13-2013, 05:51 PM  
What exactly is an 'Entry Level' Camera?
Posted By wlachan
Replies: 9
Views: 1,553
Entry camera is the one being used by an entry photographer.
Forum: Troubleshooting and Beginner Help 05-20-2013, 04:15 PM  
Is this sharp?
Posted By wlachan
Replies: 21
Views: 1,740
This lens can do sharper than that, but it is also known to be prone of misalignment due to flimsy built quality. Pretty much the story of Tamron.
Forum: Pentax Film SLR Discussion 05-18-2013, 12:59 PM  
new/old sp1000 battery cover problem.
Posted By wlachan
Replies: 18
Views: 3,297
How about drill 2 holes and remove it with a lens wrench. Better find a replacement cap first though.
Forum: Pentax SLR Lens Discussion 05-18-2013, 12:54 PM  
FA31 purchasing questions
Posted By wlachan
Replies: 75
Views: 6,153
Distant subject like scenery is great for testing sharpness, the problem is to find a perfect target that will provide meaningful sharpness at all 4 corners. The way I tested my lenses for alignment is to use the stucco wall of my house to fill the lens as much as I can with careful camera alignment with bubble lever, always shoot raw, on tripod with 2s timer. The lens must be perfectly perpendicular to the wall. Both manual & auto focus and take at least a few shots at every aperture (until f8 at least but you can go lower if you have enough patience). You would be surprised how unreliable both manual and auto focus are when viewing the results at 100%. Repeat the same test with portrait orientations (both left & right). That means for every aperture, you should have at least 3 perfectly taken samples. With these 3 samples, you can see if all 4 corners are equally sharp. The first sign of misalignment is some of the corners might appear not only diffused but seems like being pulled outward (if it makes any sense to you). Don't be surprised if one of the three samples is perfect but the other 2 are not. It means some of the glasses are being pulled by gravity due to less than perfect built quality (something most AF lenses suffer as they have to be made loose enough for AF to work).

This way, you can tell 1) how bad the misalignment is wide open (but don't be too critical because perfect specimens are rare species), 2) how much the misalignment could be combated as the lens is being stopped down, and 3) whether even sharpness is possible at f8 (the lens is a goner if not, imho). Now, if one of the wide open samples has more than just blurry corners, like one side (by whatever % of the entire image) of the image is blurry, it's a lemon. This is especially true with Pentax DSLRs because the unseen part of the FF image will only get worse. Hope I make sense to you.
Forum: Pentax SLR Lens Discussion 05-18-2013, 12:37 AM  
FA31 purchasing questions
Posted By wlachan
Replies: 75
Views: 6,153
Probably a little late to reply. Sounds like the lens should be fine, but wobble free alone does not guarantee perfect alignment, just to clarify.
Forum: Pentax SLR Lens Discussion 04-08-2013, 06:49 AM  
Anyone order the Sigma 35mm f/1.4 DG HSM for PENTAX?
Posted By wlachan
Replies: 23
Views: 3,879
Sigma has never had problem chewing out sharp lenses. The question is how's the colour rendition, boken, future compatibility and long term reliability. Things might be different now, but Sigma lenses used to use really cheap materials and designs that self-destructed within years. Their secondhand values dropped like a rock.
Forum: Pentax DSLR Discussion 04-06-2013, 11:17 PM  
If you could only have 1 lens...
Posted By wlachan
Replies: 55
Views: 4,295
An awesome FF 24/2 which is sharp wide open corner to corner. Tell me where when you found one.
Forum: Pentax Price Watch 04-06-2013, 11:12 PM  
Pentax 1000mm reflex lens: US$969
Posted By wlachan
Replies: 16
Views: 2,428
Boy that's an expensive paperweight! :eek:
Forum: Pentax Camera and Field Accessories 04-06-2013, 11:01 PM  
What is the most you have paid for a camera bag?
Posted By wlachan
Replies: 63
Views: 6,318
$3xx for an olive Billingham 445 I think, but that was more than a decade ago. Really love it, but totally impractical as a camera bag. Sold it eventually.
Forum: Pentax SLR Lens Discussion 04-06-2013, 10:54 PM  
40mm xs is f2.8 or f3.5 really?!?!?
Posted By wlachan
Replies: 46
Views: 3,859
Testing aperture blades take a few separate tests:
1) Look at the aperture blades with the camera in A or M mode. The actual stop down can be different with different orientations.
2) Check histogram with camera in M mode.
3) Check histogram with camera in A mode.
4) Compare 2 & 3 results.

Since there is certain acceptable calibrating tolerance (even stated in their parts manuals), every camera (not just model) is different. The difference could be due to the body, the lens, or that particular combo. You can fine tune lens A to match body B perfectly, but could be off again with body C. Bokeh test is not very useful here.
Forum: Pentax SLR Lens Discussion 04-06-2013, 09:09 PM  
New Pentax lens brochure
Posted By wlachan
Replies: 40
Views: 4,170
- So FA Limited are officially removed now?
- No more DA14/2.8?
- No point including any accessories that cannot be purchased outside Japan.
Forum: Digital Processing, Software, and Printing 04-06-2013, 08:51 PM  
Best laptop for processing!
Posted By wlachan
Replies: 18
Views: 3,800
I am not up to date but 99% of notebooks are aweful for processing due to the fact that their displays cannot be properly calibrated, and with horrid viewing angles. And if you don't plan to calibrate the display, you will be editing colour blinded. As to the spec, look for IPS display, i5 8GB or better. SSD for boot, 2 or more separate hard drives for at least 2 identical storage.
Forum: Pentax SLR Lens Discussion 04-06-2013, 08:35 PM  
DA 16-45 Yes or No
Posted By wlachan
Replies: 27
Views: 2,572
The reason is that at the wide end, the target is so tiny toward infinity, the wobbliness will throw the projected image out of focus (aberration due to optical misalignment is also a factor) so the camera will try to AF again and again because the focusing mechanism is so lousy on the DA16-45. The lower end 18-55s have rather firm focusing mechanism so they don't suffer the same problem.
Forum: Pentax SLR Lens Discussion 04-06-2013, 01:03 PM  
DA 16-45 Yes or No
Posted By wlachan
Replies: 27
Views: 2,572
That's because the DA16-45 has loose AF mechanism and it wobbles, while the DA18-55s don't, surprisingly.
Forum: Pentax SLR Lens Discussion 04-06-2013, 12:18 PM  
40mm xs is f2.8 or f3.5 really?!?!?
Posted By wlachan
Replies: 46
Views: 3,859
Nothing to do with firmware at all.

The aperture stop down mechanism is adjusted at 2 points - the rear lever as Dave said, or dig deeper adjusting the blades themselves. The difference is that the latter dictates the actual max wide open position which affects both the 'A' setting and manual aperture (if the lens has aperture ring). For the OP, altering the rear lever will be a quick solution which will work just fine since the 40XS has no aperture ring. Still, you want to be careful adjusting the lever on some lenses because the tiny screws can drop inside the lens and you will curse yourself to strip everything down just to get them back. Also, those screws should be threadlocked (light duty ones will do) afterward or they will loose themselves for certain. But really, once you start digging, you will find many Pentax lenses have less than precise apertures and at some point, you will just have to live with it unless you plan to find tune them all. For low bearing screws like those on the levers, philips 000 screwdriver will do (Wiha makes quality tools, Moody not, IMHO). For tight screws on the lens mount, you should look for some proper fit JIS drivers. Canon USA used to sell some high quality drivers, I don't know if they still do.
Forum: Pentax DSLR Discussion 04-06-2013, 12:31 AM  
"Upgrading" to an older model from the K2000/Km?
Posted By wlachan
Replies: 31
Views: 3,050
Why not the K-30? But if the K-m does the job, why pay more since the bodies depreciate so fast? Personally I don't recommend anything before the K-m due to poor AF performance.
Forum: Pentax SLR Lens Discussion 04-05-2013, 07:02 PM  
DA 16-45 Yes or No
Posted By wlachan
Replies: 27
Views: 2,572
I think you have had enough overlap...
Forum: Pentax SLR Lens Discussion 04-05-2013, 05:22 PM  
40mm xs is f2.8 or f3.5 really?!?!?
Posted By wlachan
Replies: 46
Views: 3,859
I don't have any video myself but there should be some if you search hard enough. I'd rather not teach how to fix it as you have never done it before, and you will likely do more damage than good.
Forum: Pentax SLR Lens Discussion 04-05-2013, 04:09 PM  
40mm xs is f2.8 or f3.5 really?!?!?
Posted By wlachan
Replies: 46
Views: 3,859
This can happen to any Pentax KA or later lens. It is not a defect for sure but rather loose QC IMHO, but doesn't seem to bother the majority of the people. When I came across lenses like that, I just fix them myself. Less pain than sending them for service which is a gamble in itself.
Forum: Pentax SLR Lens Discussion 04-05-2013, 12:43 PM  
40mm xs is f2.8 or f3.5 really?!?!?
Posted By wlachan
Replies: 46
Views: 3,859
It's a calibration issue. Pentax K mount aperture linkage requires very very precise calibration on both the body and the lens to produce accurate stop down. If either or both are slightly off (but will within spec because they accept certain tolerance in the factory), the stop down can be off by up to 1 stop (when the lens aperture is set to 'A', and 40XS is always at 'A') depend on which lens. The aperture blade should stop down at f3.5 even by slight amount (maybe 1mm). If not, the lens can be readjusted easily by any technician. If it's new, better exchange it if it bothers you. Also, mechanical aperture is not perfectly linear so the actual exposure will vary as you stop down, and the difference can be quite dramatic.
Forum: Pentax SLR Lens Discussion 04-02-2013, 03:07 AM  
HELP! lens fell & cracked :( URGENT
Posted By wlachan
Replies: 15
Views: 2,084
An impact like this will likely result in optical misalignment which only Tamron will be able to fix, if possible at all.
Forum: Pentax SLR Lens Discussion 04-02-2013, 03:01 AM  
SDM problem.
Posted By wlachan
Replies: 17
Views: 1,434
I suggest whoever have insisted the SDM problem had be addressed, should pay for these repairs due to spreading false information.
Forum: General Talk 04-02-2013, 02:38 AM  
Seller Protection on Paypal?
Posted By wlachan
Replies: 10
Views: 969
"Tracking" is the key. Ship it with tracking # so that Paypal will be able to confirm the package was shipped and delivered. The proof of shipping alone is not enough, I know as I was burnt before. Also, make sure the payment was "cleared" before shipping.
Forum: Pentax SLR Lens Discussion 03-29-2013, 12:53 AM  
da 15 fell to ground with tripod
Posted By wlachan
Replies: 9
Views: 1,227
Don't force anything. The distorted parts have to be replaced.
Forum: Pentax SLR Lens Discussion 03-28-2013, 02:34 PM  
FA31 purchasing questions
Posted By wlachan
Replies: 75
Views: 6,153
Exactly how I feel as well. But I must emphasis this feel had nothing to do with the actual toughness after figuring out the cause.
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