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Forum: Pentax News and Rumors 03-19-2012, 01:08 PM  
K-r successor: K30
Posted By Radix
Replies: 653
Views: 111,995
Looks like K-z to me after resizing and Topaz InFocus treatment.
Forum: Pentax DSLR Discussion 03-31-2011, 08:07 AM  
K-x Firmware 1.02
Posted By Radix
Replies: 44
Views: 14,551
I have the same problem with 1.02. It seems that normally (with 1.01) in live view K-x uses aperture 4 for preview and with firmware 1.02 it uses aperture wide open. The problem is that the camera still thinks it is using aperture 4 instead of 1.4 (or anything else wider than 4) and therefore calculates the exposure wrong. The same problem is in movie mode if you lock exposure before recording. If you set the green button to optical preview and hold it in live view and then lock the exposure, it will calculate it correctly.
Forum: Monthly Photo Contests 02-19-2011, 10:56 AM  
Icy River
Posted By Radix
Replies: 0
Views: 990
Icy River
Film: Kodak Portra 400
Forum: Monthly Photo Contests 12-19-2010, 03:38 AM  
Special Event Pentax Holiday Giveaway: 35mm Lens (Entries go here)
Posted By Radix
Replies: 206
Views: 39,263
My Helios 44 review (second review for this contest):
KMZ Helios 44-2 58mm F/2 Lens Reviews - Pentax Third-Party Lens Review Database

Approved!!
Forum: Monthly Photo Contests 12-15-2010, 01:37 PM  
Special Event Pentax Holiday Giveaway: 35mm Lens (Entries go here)
Posted By Radix
Replies: 206
Views: 39,263
Forum: Video Recording and Processing 12-01-2010, 10:52 PM  
Sticky: The Guide To Manually Controlling Video Exposure on The K-7
Posted By Radix
Replies: 98
Views: 118,041
If you have aperture control in video mode set to auto, then it behaves like that with K-x.

It seems that auto in that setting changes movie mode to some kind of P-mode and manual to some kind of Av-mode.
Forum: Monthly Photo Contests 10-30-2010, 10:33 AM  
Green Droplets
Posted By Radix
Replies: 0
Views: 2,207
Green Droplets
Forum: Pentax SLR Lens Discussion 10-29-2010, 07:37 AM  
Sigma 30mm f1.4 sample photo request
Posted By Radix
Replies: 32
Views: 10,966
I have the Sigma 30mm lens and I like it. Center sharpness is great at all apertures and corners don't matter that much in most of my images. With landscape photos you can see the softness there if you look 100 % size but it's only very soft in the area of ~20-30 nearest pixels to the corner. Therefore it can be cropped away if it bothers, but usually you won't even notice it if not looked at 100 %.

I uploaded a few photos taken with this lens at different apertures to Flickr:
Sigma 30mm f1.4 - a set on Flickr
Forum: Video Recording and Processing 07-23-2010, 12:54 PM  
K-x video samples
Posted By Radix
Replies: 157
Views: 42,429
A few months ago I posted a music video in this thread. Here's another one that I shot at the same time.

Equipment: Pentax K-x mostly with Helios 44M lens at f2.0 (some parts with Auto Chinon 135 mm f2.8 M42), Olympus LS-10 sound recorder for audio

[yt]http://www.youtube.com/watch?v=f62rRbOaTLs[/yt]
Forum: Pentax DSLR Discussion 07-22-2010, 07:36 AM  
Shutter induced blur with the Pentax K-7 camera
Posted By Radix
Replies: 9
Views: 4,393
I noticed the same effect with K-x a short while ago. I got sometimes blurry pictures with 1/60-1/200 shutter speeds and wide angle lenses, so I did some tests and got similar conclusions as LumoLabs, but I wasn't sure if it was caused by shutter although it seemed so. Thanks to LumoLabs people for doing this research. Before this research I though that my camera could be broken.

Because of this blur effect I have been avoiding those shutter speeds with 18-30 mm focal lengths and have gotten much less blurry pictures.
Forum: General Talk 04-07-2010, 10:34 PM  
Announcing the PentaxForums Million-Post Giveaway
Posted By Radix
Replies: 1,243
Views: 198,564
I'm in. Best contest on this forum.
Forum: Video Recording and Processing 03-23-2010, 03:54 AM  
K-x video samples
Posted By Radix
Replies: 157
Views: 42,429
I recorded it with an external Olympus LS-10 recorder using its internal stereo mic.


Yes, I used AE lock all the time and set it in AV mode. The video was shot with lowest contrast and a bit lower saturation than normal. I corrected levels and colours in VirtualDub and removed noise with NeatVideo. The editing was done in Linux with Cinelerra.


Only one K-x was used. The video was made from three different plays of the same song.


Almost all of the video was shot with Helios 44M lens at f2.0. Some parts were shot with Auto Chinon 135 mm f2.8 M42 lens.
Forum: Video Recording and Processing 03-22-2010, 03:32 PM  
K-x video samples
Posted By Radix
Replies: 157
Views: 42,429
Here's a music video I shot with Pentax K-x: YouTube - Oot Meidän Kuningas
Forum: Video Recording and Processing 03-16-2010, 12:20 PM  
Maybe An Email Camapign To Persuade Pentax To Give Us Full Manual Video Mode
Posted By Radix
Replies: 136
Views: 23,213
If I lock exposure in Av mode to 1/50 s and ISO 200 and switch to video mode, video is recorded at ~1/25 s and ISO 100 (it won't show those values but you can see it from the footage that it is about 1/25 s shutter speed). AE lock locks only exposure value, not ISO or shutter speed.
Forum: Video Recording and Processing 03-15-2010, 11:31 PM  
Maybe An Email Camapign To Persuade Pentax To Give Us Full Manual Video Mode
Posted By Radix
Replies: 136
Views: 23,213
I agree. The biggest problem is that you cannot use ~1/50 s shutter speed with anything else than ISO 100, which can be very dark in lower light.
Forum: Pentax DSLR Discussion 03-15-2010, 04:07 AM  
catch in focus?
Posted By Radix
Replies: 40
Views: 7,896
With debug mode you can use catch in focus with any focus point: https://www.pentaxforums.com/forums/pentax-dslr-discussion/88186-off-center-m...bug-k100d.html
Forum: Video Recording and Processing 03-10-2010, 11:38 PM  
flickering and colour shift in video
Posted By Radix
Replies: 15
Views: 6,649
I did a new test. Now it seems that there is also a point of exposure bellow which the flickering starts again. I locked the exposure and used exposure compensation to see when the flickering occurs. Now it didn't occur when the exposure was from 1/40 s to 1/25 s at ISO 100 (I checked it in av mode while the exposure was locked) but it occured with 1/50 s and 1/20 s. Yesterday I remember that the exposure in av mode was 1/13 at ISO 100 when there was no flickering (that's about 1/25 s at ISO 200 in video mode). Therefore it seems that the non-flickering exposure value changes from time to time. I can see the flickering also in live view mode when taking still photos.

Edit: I noticed that there can be still some flickering in the videos taken in the non-flickering exposure values, but it is very rare. There was only 1 red flicker in a 11 second non-flickering video but many flickers per second in flickering videos.

Edit 2: It seems that a quite reliable way to prevent flickering is locking exposure to 1/40 s ISO 100 in av mode and switching then to video mode (with manual lens).
Forum: Video Recording and Processing 03-10-2010, 01:30 PM  
flickering and colour shift in video
Posted By Radix
Replies: 15
Views: 6,649
I did some further testing trying to find out when the flickering occurs and when not. It seems to be much more probable that there is flickering in a video than no flickring.

I found out that there seems to be a certain level of exposure, bellow which the flickering stops suddenly and completely. For example when exposure is locked at a certain level, there's no flickering at -2/3 ev compensation, but at -1/3 ev compensation the flickering starts. I also found out that changing the aperture from a manual lens doesn't affect flickering at all although the light coming to the sensor changes. I did these tests with locked white balance, sr on, custom image settings all to normal except minimun contrast and in artificial lightning (50 Hz). The 50 Hz lightning didn't cause the flickering, because the same flickering occured also when I filmed outside of my window and electricity causes different kind of flickering (I saw that when I used certain shutter speeds). The camera got hot during these tests but it didn't affect the flickering at all and I got videos with no flickering at the end of the testing.
Forum: Video Recording and Processing 02-22-2010, 02:19 PM  
flickering and colour shift in video
Posted By Radix
Replies: 15
Views: 6,649
I uploaded that video to Vimeo (you can download the original): Pentax K-x colour flickering problem on Vimeo
Forum: Video Recording and Processing 02-22-2010, 05:35 AM  
flickering and colour shift in video
Posted By Radix
Replies: 15
Views: 6,649
My K-x seems to produce this colour flicker. It is quite annoing in videos and also strange, because it doesn't appear always and I haven't found any consistency when it happens.

I did a test. SR off, camera on a table, white balance set to daylight, exposure locked in AV to ISO 100 and 1/50 s and then switched to video mode (shadow and highlight corretion off). The only source of light was the sun, so the flicker can't be due to 50 Hz electricity. The result was that there's random red flicker in the whole video clip and each flicker appears only in one consecutive frame. And when there's a flicker, it is evenly distributed on the whole frame.

There's an example image in the attachments. I took three 100% crops of concecutive frames from the same area.

Right after taking that video I did a new one locking exposure to ISO 1600 and 1/25 s and filming the same scene. I can't see any flicker in that video. That's why I think that the heating of the sensor isn't causing this, because it should be warmer in the latter video.

Edit: There seems to be two different kinds of flicker in the flickering videos: red and green. And the normal, non-flickering parts of flickering videos are neither red nor green.
Forum: Film SLRs and Compact Film Cameras 02-21-2010, 07:59 AM  
SFXn autofocus problem
Posted By Radix
Replies: 3
Views: 2,734
That's the only lens that I have with autofocus and I don't have any friends with Pentax lenses. It could be possible, that the lens isn't completely recognised, but it would be strange, because the camera shows its aperture correctly and autofocus works well if the subject is closer than the current focus before autofocusing.

According to manual the camera shouldn't show solid > sign when using autofocus at all. In manual focus mode it means that you have to focus further.
Forum: Film SLRs and Compact Film Cameras 02-21-2010, 01:32 AM  
SFXn autofocus problem
Posted By Radix
Replies: 3
Views: 2,734
I just bought a used Pentax SFXn camera. Otherwise it seems to work well, but autofocus works only in one way, from far to near. The motor doesn't seem to rotate in the other direction. I have to switch it to manual focus in order to focus further. When it should focus further with autofocus, it only shows a solid > signal in viewfinder. The lens I am using is the K-x kit lens, DAL 18-55mm. It works well with K-x, so the problem doesn't seem to be there (the imaging sircle is too small when zoomed <24mm, but from that on it fills the frame). Do you have any suggestions what could be wrong with the camera or if it could be fixed easily?

I won't return the camera because it was so cheap and I have many manual focus lenses, but it would be very nice if autofocus worked correctly.
Forum: Pentax DSLR Discussion 01-26-2010, 04:54 AM  
Off-center MF Confirmation with Debug K100D!
Posted By Radix
Replies: 14
Views: 5,335
I was wrong, it works just as you described. But "AF Area Test" has to be 2 (default was 0) and "AF Area Number" can be 0. Then it focuses on the selected focus point. The only difference between this and using an AF lens is that it shows still only the center point on the main screen although another focus point is selected and used.

If I exit debug mode it stops working. It's a shame that you have to be in debug mode, because the development menu appears every time I turn the camera on.
Forum: Pentax DSLR Discussion 01-25-2010, 10:56 PM  
Off-center MF Confirmation with Debug K100D!
Posted By Radix
Replies: 14
Views: 5,335
That's a great finding! I've been wanting that feature. I got it working with my K-x. You have to put "AF Area Test" to 1 and "AF Area Number" to a different numer (different numbers are different areas). It works also with catch in focus.
Forum: Video Recording and Processing 01-22-2010, 01:28 AM  
noise reduction quality in video mode
Posted By Radix
Replies: 6
Views: 14,454
I have found out that you can reduce noise very well in post prosessing without getting smudgy looking video. Avidemux (Avidemux - Main Page) works very well when using its MPlayer hqdn3d noise reduction filter with settings 0 for spatial luma strength, 5-15 for spatial chroma strength and 3-6 for temporal strength. The settings depend on how noisy the video is. I prefer not to use luma noise reduction at all, because it creates easily smudgy video. This way I mainly remove colour noise.

Edit: Here are two images, first one is without noise reduction and the second one is with 0 luma, 30 chroma and 6 temporal noise reduction. They are 100% crops of the same video frames. It was pretty dark outside when this was filmed.
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