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Forum: Pentax News and Rumors
07-06-2011, 06:06 PM
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I hope they reviewed the essentials: facial recognition, scene modes, art filters and the zoom range of the kit zoom.
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Forum: Winners' Showcase
06-27-2011, 01:56 AM
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A big thank you to all of you that voted for my entry- most appreciated.
Cheers, Gary Hickin
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Forum: Pentax Q
06-24-2011, 12:39 AM
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For me personally, pricing is a bit of an issue for the Q - especially when compared to the GRDIII, the LX5 and the X-Z1. But that simply means it isn't for me. I'm one of those waiting for a serious mirrorless or a Pentax FF.
But I quite honestly don't get all the hate for the Q. Personally, I know more people who'd rather drop the $1640 for the Q than pay cheaper for a Kr + 18-135. For those people, toting around a DSLR to a club or to a party just doesn't make sense. The Q makes a hell of a lot more sense to them.
Though IMO, Pentax dropped the ball on the launch by not including samples from the two toy lenses and the fish-eye. IMO, those three lenses are the biggest selling point of this system.
$800+ $80x2 for the prime kit plus the two toy lenses might sound a bit too much - but considering that most people who use Holga's (at least here in the Philippines) are the people who willingly drop $300-400 on a Lomo LCA or 4 different Lomo cameras - instead of the spending the same amount on an LX5/G12 etc.. not to mention at least $100-200 per month buying and developing 120 film - which means for them, dropping $1000 for a digital Lomo 2 lens kit + fast normal prime, is probably a pretty good deal.
I do get what Pentax was trying to do here. Pricing is my only beef with it, but I think street price will probably be closer to advanced compacts. I have no issues with the sensor size at all. Personally, I think Pentax would make more money from the Q vs a DA 500mm f/4, or a DA 300mm f/2.8, but that's just me.
But with that said, if Pentax wants to be different, I'd rather they come out with something like a digital TLR, or a no-frills Full Frame - no movie mode, just 3fps, just 3 AF points - a Full Frame Nikon D40 if you will - except sized like the boxy film FFs of old and priced below USD $1500. If you're going to be quirky, I'd rather they do it in style. Personally, I'd rather drop the cash on those than a D700 or a 5d clone or even a D3x clone.
If I wanted a sports-shooting or wedding shooting Full Frame, NiKanon already have those. If Pentax came out with a D800 clone at the same time that the real D800 came out - how many people do you think would buy it? Only people with the FA Limiteds. For most people, they'd rather buy the Nikon or the Canon.
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Forum: Pentax Q
06-23-2011, 01:33 AM
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Yep, 1600 iso looks impressive.
If the price drops heavily, for macro & tele, why not ?
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Forum: Site Suggestions and Help
05-16-2011, 09:01 AM
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Hi
I too feel a Binoculars section would be very welcome. +1 from me for that.
There are many bird enthusiasts who would appreciate it.
Digiscoping and related subspeciality areas would also open up for discussion.
Sridhar
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Forum: Pentax News and Rumors
04-22-2011, 11:17 PM
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What could be happening is that, in a vert. column, only every 2nd pixel is read in a pass (for speed?), maybe alternating between passes, so that would mean that out of 5120 pixels in a column, 2160 effective pixels are read at a time.
4.2 μm * sin 45° * 5120 = 12.8 mm height
Dan
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Forum: Pentax News and Rumors
02-03-2011, 11:43 AM
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It's Kenko system. 14 Mp, 1/2.33" sensor and C-mount.
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Forum: Troubleshooting and Beginner Help
11-03-2010, 02:47 PM
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Remember extension tubes can also be used to reduce the minimum focusing distance of long lenses, to allow it to focus on say small birds ect.
They don't have to be only for macro.
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Forum: Pentax News and Rumors
10-30-2010, 04:07 AM
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- Whether *most poeple* notice it, is irrelevant for the existence of a problem.
- Maybe Falk is trusted with testing cameras (he already was an alpha-tester for the K-7) because he doesn't jump to conclusions like some here.
You mean by avoiding the relevant shutter speed range? You may want to call that "workaround", I call it serious limitation.
May I ask what makes you assume the camera is going to be a gift? I reckon he has to return it after having had a good look at it. I might be wrong, but I'm not making assumptions and start to accuse/question people based on speculations.
Regarding the potential of the manufacturer selecting a specific sample:- Pentax (UK) didn't manage to send DPRreview one single copy of a DA* 55/1.4 that didn't have an optical problem. Three attempts, three failures even though the recipient was known.
- If Pentax can manufacture one camera that doesn't have the problem than that's just dandy. Everyone having an issue then will then be able to refer to that copy and say "I want a defect-free one as well". Where is the issue?
Perhaps because Pentax acknowledged the problem? Don't you know that Pentax specifically agreed that Falk and his team go public with there observations? There is no doubt that at least some copies (if not all) of the K-7 had the problem. That not all users noticed the problem doesn't say anything.
Have you read Falk's article about the shutter blur issue? Would you like to care to point out to us where the "hidden flaw" might be?
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Forum: Photographic Technique
10-29-2010, 03:49 AM
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well there is the answer right there, because of the legacy compatibility that Pentax has opted for, it makes it difficult for pentax to bump the ISO figures.
I have a pentax 50mm f/1.2 in both A and K versions and there is no difference between the exposures on each lens, on either the K10D or the K-7.
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Forum: Pentax News and Rumors
10-15-2010, 07:02 AM
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Well, I have to admit I was maybe wrong saying that the 1/180 limit was physical (shutter) and faster x-sync was impossible, and those waiting for a miraculous firmware update were daydreamers...
After careful examination of the P-TTL patents (Patent #6,718,135 for those interested), I think I've found out why P-TTL is limited to 1/180...
EDIT: in fact, this patent describes an early implementation of P-TTL, and it was slightly modified since, so what you're about to read is false!
In fact, in wireless mode, the main flash (built-in or external) issues during the exposure a preliminary low-power flash burst prior to its main burst to sync the slave flashes. There is then a 3ms wait between this low-power synch burst and the main flash...
And in all modes, there is at least a 1ms wait between the main flash and trailing curtain to let the flash reach its max power.
Sequence is :- Leading curtain
- wait for half the Tv (this one I'm not sure about, maybe they mean Tv to be the X-sync duration.)
- if wireless: (EDIT: This is the part that was modified)
- low-power synch burst
- 3ms wait
- Main burst
- 1ms wait (to allow the main flash burst to fully occur)
- Trailing curtain (to occur when Tv is reached)
So in wireless, there is already 4ms spent in waiting... It translates to 1/250 (+ the Curtain travel time) being the fastest speed at which we can do the waiting!!!
From this we can conclude that Curtain travel time is less than 1.5ms, or 1/640, by the way : as time difference between 1/250 and the 1/180 x-sync is 1.5ms, and we can hope they haven't squandered precious time elsewhere...
So, theoretically, the fastest x-synch that you could attain with an instantaneous flash burst should be 1/640 with the current shutters... Allow for some time for longer (and realistic) flash burst (Canon 550ex has a max flash duration of 1.2ms, for instance), and you end up with roughly 1/360 being the fastest x-sync you can have with modern flashes... If you keep the 1ms wait mentioned in the patent, you end up with a 1/400 shutter speed.
EDIT: the following sentence was proved false in the subsequent dialog... (The error was coming from the wireless mode needing those 3ms, as it was proven to be false and the sync burst is done right before the exposure)
SO IT SEEMS IN FACT TRUE THAT 1/250 (and even 1/360) CAN BE OBTAINED THOUGH A FIRMWARE UPDATE! (as long as you don't use wireless, though).
And it should be compatible with all existing Pentax DSLRs and Flashes!!!
All this is caused mainly by the wireless waiting time...
It's a pity they limited the whole flash system this way.
I guess they set the x-sync the same for wireless and standard because:
1) it would have confused people otherwise, or
2) wireless would have got flamed for being slower than standard flash...
Could someone verify all this?
(and next time I'll do the math before opening my big mouth!!!)
So maybe we will see two x-sync speed from now on : standard (1/250 or maybe even 1/360) and wireless (1/180)...
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Forum: Sold Items
10-09-2010, 06:22 PM
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PentaxForums.com Marketplace Listing
Item for Sale
Pentax F 1.7x AF Adapter (Mint)
Asking Price
US$335
Item Location
Tokyo, Japan
Item Description
Pentax F 1.7x AF Adapter
I have 4 available for immediate shipment.
Item condition:
- Brand new, unused.
I would rate the condition of this converter as mint. This item is un-opened box, never used. This item comes with open warranty certificate, but I'm not sure if Pentax warranty is transferable from the original owner (me). For obvious reasons, I'm unable to supply the original purchase receipt. It would be best to assume that this item has no manufacturer's warranty. I am, however, willing to offer a 30 day money back warranty in the unlikely event that something goes wrong.
Item description:
This converter is suitable for all digital and 35mm film SLR cameras, which has a Pentax K-mount.
This adapter needs no introduction. If you're looking at this listing, you should know all the details already. However, to be fair to the newbies, I will state that this adapter not only works as a 1.7x teleconverter, but it also adapts an older manual focus lens into an autofocus lens. So, in effect, your 50mm f1.4 manual focus lens becomes an 85mm f2.5 autofocus lens!
Other included items:
- This converter comes complete with both front and rear caps, soft pouch, instruction manual (Japanese), warranty certificate (see note above), and box as per original package.
See picture below.
Images:
Click on images for a larger view.
Complete package
Payment method:
- I can only accept payment via PayPal. Please complete your payment process as promptly as possible to avoid delays in shipping.
Postage and handling:
- Item will ship from Japan via EMS (Express Mail Service), usually within 2 business days after receipt of payment.
- Item should arrive at your destination in 5~10 days after despatch. However, this is an estimate only and may vary considerably depending on many circumstances.
- I can provide tracking number and web address to check the progress of your parcel.
- Item will be shipped to your PayPal registered address only.
- Insurance is included in the postage.
Custom duties and taxes:
- Any duties and taxes payable upon entry into your country is YOUR RESPONSIBILITY.
- Please research your country's laws and regulations carefully before buying.
Returns policy:
- 30 day money back warranty. Usual policy applies. (e.g. Does not cover accidental damage, abuse, etc.)
- All returns must be pre-approved and packaged properly.
Are you the original owner of the item being sold?
Yes
Are you selling or trading this item?
Selling
Item Condition (Key)
New
Shipping Destinations
Worldwide
Shipping Charge
US$22 - US, Canada, Australia. Please enquire for others.
Shipping Services
EMS (Express Mail Service)
Accepted Payment Types
PayPal
Return Policy & Additional Details
Please refer above for full details.
Please send me a private message if interested in the item!
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Forum: Pentax SLR Lens Discussion
07-26-2010, 09:21 AM
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Expect lots of discussion on this one. I'll try to summarize:
There have been numerous reports from individuals of the SDM AF mechanism failing in various DA* lenses. The primary symptoms have been no, or exceptionally slow response to attempts to us AF (e.g. shutter release button half-pressed and lens takes 10 or more seconds to respond). Suffice it to say that there have been more reports from owners of the more popular lenses (notably, the DA* 16-50 and the DA*50-135). While it has been acknowledged that any electronic mechanism that is mass-produced will have a failure rate greater than zero, there is heated debate regarding whether Pentax SDM failure rates are excessive, compared with other manufacturers with similar technologies (Nikon's AF-S, Canon's USM, Sigma's HSM and Sony's SSM). There have been various surveys taken in an attempt to quantify the frequency of these failures. However, the statistical validity of these surveys has been called into question on the basis of sampling bias - those with problems are more likely to participate in these discussions/surveys than those without. To my knowledge, Pentax has never publicly acknowledged any problems associated with the SDM technology itself. Rather, failures have been treated as isolated incidents, with repairs made under warranty (if the failure occurred during the warranty period). This has frustrated numerous Pentax owners, who have experienced SDM failures shortly outside the warranty period (1 year in the US, 2 years in Canada, not sure about Russia). Often, the sufficiency of the warranty period is called into question, as other manufacturers have longer warranty periods on their "professional" lenses.
With that out of the way, I think the first step for you is to rule-out any problems with the settings and set-up of your camera:
1) Verify that the AF mode switch on camera body is set to "AF-C" or "AF-S"
2) Verify that the AF mode switch on the lens is set to "AF"
3) Inspect and clean the electrical contacts between the lens and camera body to ensure a good connection.
4) Ensure that you have the AF function on the camera body set-up correctly. There is a custom menu option that allows you to engage the AF system when you half-press the shutter release button, or when you press the AF button on the back of the camera. Make sure this setting is consistent with how you expect to engage the AF system.
5) Since you have a K-7, no firmware updates are necessary - on the K10D, only v1.30 supports SDM and earlier Pentax models do not support SDM at all (they default to screw-drive AF).
Best of luck!
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Forum: Pentax Lens Articles
08-15-2008, 10:33 AM
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Ok, even although I did't get much response for my work I'll continue with the DA* 300mm here...
Test procedure is as described in post #28.
Fill-factor with the DA*300 test shots: 97.3%
Test shots (red line marks the APS-C image circle):
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f/4:
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f/4.5:
Center crop supersampled from two test shots at 10000 dpi (f/4.5):
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f/6.7:
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f/8:
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f/11:
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f/22:
(click onto images for full scale 5062 dpi images)
Note: there is some blur in the images. The images were taken on tripod with mirror lock-up and 3s timer release (the best the *ist has on offer). There still is shake visible, probably from the curtain. But because it is almost in one direction only, it is still possible to evaluate results. German magazine FOTOmagazin doesn't use film with tele anymore because they say that the shake is too strong due to low ISO 100 of high resolution B&W film used. And my film even is 20 ISO! Obviously, it is a problem to measure long tele lenses with film. I did my best here :ugh:
Numerical evaluation (first figures: as read from small charts) (second figures: in LW/PH):
Center (f4 / f4.5 / f6.7 / f11): (6 / 7 / 7 / 7) (2400 / 2900 / 2900 / 2900)
APS-C corner (f4 / f4.5 / f6.7 / f11): (5 / 6 / 7 / 7) (2000 / 2400 / 2900 / 2900)
FF corner (f4 / f4.5 / f6.7 / f11): (3 / 4 / 5-6 / 5-6) (1200 / 1600 / 2000-2400 / 2000-2400)
FF vignetting (f4 / f4.5 / f6.7 / f11): (++ / ++ / +++ / +++)
(for vignetting, see the church image as well; again, the Adox contrast makes it more dramatic than it really is).
The full frame corner resolution at full aperture is ~50% of the center resolution. While FF glass with this characteristics does exist, it would not qualify as the excellent lens the DA*300 is on APS-C.
My biggest complaint is a sort of ghost or shadow image visible in the extreme FF corners. This lowers the corner resolution in one direction (why I gave a range above). This effect doesn't go away when stopping down. It is probably due to lateral chromatic aberration which leads to purple fringing at all apertures.
Assuming it is CA_lat, I can give its size for the extreme FF corners here (measured in the lower right corner at f/6.7):
CA_lat = 4 px = 20 µm.
Typical photozone.de figures are 0.5 px (K10D) or 3 µm.
Therefore, we must conclude that CA_lat is out of control at extreme FF corners for the DA* 300mm.
Final verdict:++ (upgraded after comment of Pål Jensen) Worse FF than with APS-C, but usable at full aperture with a medium loss in corner IQ. Usable starting at ~f/5.6 with a small loss in corner IQ only.
I reserved the option to change the rating because I don't know yet how a true full frame tele lens does perform in its extreme corners.
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Forum: Pentax News and Rumors
07-09-2010, 05:35 AM
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I second this. A K-7GS (grayscale) perhaps?
One thing I keep thinking about regarding this design is how much sensitivity improve and resolving power would improve. Remove Bayer filter and each photosite (in fact, now a true pixel in a grayscale sensor) would get much more light, at least two stops is my guess (depends on how narrow are RGB photosite filters), and since there is no interpolation, resolving power would easily double, which is in fact already demonstrated with Foveon X3 vs. Bayer pattern sensors, (4.6MP X3 comparable 10MP Bayer).
However, the native base ISO would go to ISO 400 (or more) from ISO 100 assuming the same sensor. And here is the thing: why the same sensor? A much more efficient sensor could be made for, say, ISO 50-3200 with SIGNIFICANTLY better signal to noise ratio. A dream machine for superclean and supersharp BW images! I think there is a market for such camera, and I would certainly consider getting one.
(And I still have my color filters for BW photography!)
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