Focus test of the K-5
Please excuse if multiple copies of this come through. My friend upgraded the server that he hosts my account at, and things have been completely hosed and unreliable for the past week. All morning mac mail has been insisting that the smtp server is offline, and hasn't let me correct that. The night before last I had a whole series of photos of a musician front focus on his microphone, despite it being no where close in the frame to the focus point. The light was reasonably bright, but it was tungsten. So, tonight, being the nerd that I am, I decided to test how color affects focusing. I took assorted gels that I had around, and also a couple of green bulbs set up a few test setups. As far as I could tell under red light the K-5 did front focus. It also seems to front focus under blue light. For this run of the test. I tried to defocus the lens between each shot. Shot using tungsten, blue gel, yellow gel, CTO gel, red gel, green incandescent, and a green CF bulb. Focus point set on the focusing chart. I haven't done a test yet to determine whether it just front focuses under low light, or whether it front focuses because of lack of light in the green channel. ISO 80, 77/1.8 wide open, shot at 1.8, attempting to keep exposure even. I also processed each shot both as color and black and white. Crops: http://www.flickr.com/photos/ellarsee/sets/72157632954496070/ Crops on fluidr http://www.fluidr.com/photos/ellarsee/sets/72157632954496070/ Uncropped: http://www.flickr.com/photos/ellarsee/sets/72157632950174733/ On thursday night we had me with the K-5, Danielle with a D700, Michael with a 1D4 and Scott with an OM-D. It'll be interesting to compare everyone's photos. Mine, I'm afraid, did not turn out well. Apparently both Danielle and Igor think that I obsess a bit too much on monopods for low light work. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Focus test of the K-5
Apologies in advance for what may be a dumb question(s) . . . Are all of these tests using autofocus? Assuming yes, then - You say the focus target was the focusing chart. Did you use the viewfinder and/or liveview to verify that the system was focused on the target? And not on the numbers on the ruler or some other point? - What happens with the same setup if you manually focus? I am trying to grapple with what are the possible failure points in the AF process . . . stan On Mar 9, 2013, at 3:09 PM, Larry Colen wrote: Please excuse if multiple copies of this come through. My friend upgraded the server that he hosts my account at, and things have been completely hosed and unreliable for the past week. All morning mac mail has been insisting that the smtp server is offline, and hasn't let me correct that. The night before last I had a whole series of photos of a musician front focus on his microphone, despite it being no where close in the frame to the focus point. The light was reasonably bright, but it was tungsten. So, tonight, being the nerd that I am, I decided to test how color affects focusing. I took assorted gels that I had around, and also a couple of green bulbs set up a few test setups. As far as I could tell under red light the K-5 did front focus. It also seems to front focus under blue light. For this run of the test. I tried to defocus the lens between each shot. Shot using tungsten, blue gel, yellow gel, CTO gel, red gel, green incandescent, and a green CF bulb. Focus point set on the focusing chart. I haven't done a test yet to determine whether it just front focuses under low light, or whether it front focuses because of lack of light in the green channel. ISO 80, 77/1.8 wide open, shot at 1.8, attempting to keep exposure even. I also processed each shot both as color and black and white. Crops: http://www.flickr.com/photos/ellarsee/sets/72157632954496070/ Crops on fluidr http://www.fluidr.com/photos/ellarsee/sets/72157632954496070/ Uncropped: http://www.flickr.com/photos/ellarsee/sets/72157632950174733/ On thursday night we had me with the K-5, Danielle with a D700, Michael with a 1D4 and Scott with an OM-D. It'll be interesting to compare everyone's photos. Mine, I'm afraid, did not turn out well. Apparently both Danielle and Igor think that I obsess a bit too much on monopods for low light work. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Focus test of the K-5
On Mar 9, 2013, at 5:51 PM, Stan Halpin wrote: Apologies in advance for what may be a dumb question(s) . . . Are all of these tests using autofocus? Yes, all of them were with autofocus. Assuming yes, then - You say the focus target was the focusing chart. Did you use the viewfinder and/or liveview to verify that the system was focused on the target? And not on the numbers on the ruler or some other point? I mounted the camera on the tripod. Selected the focus point on the focus chart. IIRC, it was the upper right focus point. I did not reset the focus point, but I would put my hand in front of the lens. and touch the shutter to get it to defocus. I then pressed the shutter, the camera would focus and then take the photo. I heard the focus motor whir. For each lighting set up, I'd repeat several times. For each lighting setup I'd adjust the shutter speed based on the histogram. Auto exposure in monochromatic light results in one channel being blown out, and two channels still being way underexposed. - What happens with the same setup if you manually focus? I didn't try that. This was actually about the third or fourth series I ran. On the first set, I had center focus, centered on the focus chart. The plane of the focus chart was even with the wig dummy's eyes. http://www.flickr.com/photos/ellarsee/sets/72157632961487174/ or http://www.fluidr.com/photos/ellarsee/sets/72157632961487174/ I am trying to grapple with what are the possible failure points in the AF process . . . I kept hearing about the problems with K-5s front focusing in tungsten light. Usually, when I have problems with front focusing, it is tungsten light, but there is also a microphone in front of the subject, even if the focus point is on the other side of the screen. I tried to come up with a quick experiment that I could do that would shed some light on the issue. I don't have the time I need to properly investigate the issue. One thing that should be done would be to set up a focus chart, and have a yard stick going diagonally across the screen to get a better feel, and quantification, of front and rear focus. What I expected was that red would front focus and blue would rear focus, but that didn't seem to be the case. It would be interesting to do an experiment with light levels and focusing. It is possible that the front focusing has more to do with light level than it does with color temperature. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Focus-Test
http://www.zimbio.com/member/k10dbook/articles/1701411/PART+2+Autofocus+Adjustment+Pentax+K20D+Custom Cheers, .t -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Focus-Test
Good news can spread widely. :-) Here's the blog of the guy who made the chart: http://pentaxdslrs.blogspot.com/2008/06/part-1-autofocus-adjustment-for-pentax.html Jostein 2008/9/4 [EMAIL PROTECTED]: http://www.zimbio.com/member/k10dbook/articles/1701411/PART+2+Autofocus+Adjustment+Pentax+K20D+Custom Cheers, .t -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- http://www.alunfoto.no/galleri/ http://alunfoto.blogspot.com -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: K10D focus test shot
http://photo.net/photodb/photo?photo_id=7024445 Here is the head shot. Focus point is on her left eye. DA 50 F2.8 at f2.8 No PS as is from camera. Dave On Thu, Mar 6, 2008 at 7:27 AM, David J Brooks [EMAIL PROTECTED] wrote: http://photo.net/photodb/photo?photo_id=7024435 Focus point is on the blue light. The yellow light is more in focus. When i focused on the yellow light, the one behind is in focus. F 2.8 used. I did some test shots, head shots of the SO and they are fine at f2.8. Looks like if it has enough to focus on, it does, but Dave -- Equine Photography www.caughtinmotion.com http://brooksinthecountry.blogspot.com/ Ontario Canada -- Equine Photography www.caughtinmotion.com http://brooksinthecountry.blogspot.com/ Ontario Canada -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
K10D focus test shot
http://photo.net/photodb/photo?photo_id=7024435 Focus point is on the blue light. The yellow light is more in focus. When i focused on the yellow light, the one behind is in focus. F 2.8 used. I did some test shots, head shots of the SO and they are fine at f2.8. Looks like if it has enough to focus on, it does, but Dave -- Equine Photography www.caughtinmotion.com http://brooksinthecountry.blogspot.com/ Ontario Canada -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: K10D focus test shot
I did the quick and dirty 45 degree shot of text with the FA 50 at f1.4. With 12 point double spacing, the focus is best on the line above the chosen one. The chosen text is in acceptable focus, however. I can see cases where it could be a problem, but now that I know I'll be sure to check and maybe even bracket focus a bit after checking the screen. Steven Desjardins Department of Chemistry Washington and Lee University Lexington, VA 24450 (540) 458-8873 FAX: (540) 458-8878 [EMAIL PROTECTED] David J Brooks [EMAIL PROTECTED] 3/6/2008 7:27 AM http://photo.net/photodb/photo?photo_id=7024435 Focus point is on the blue light. The yellow light is more in focus. When i focused on the yellow light, the one behind is in focus. F 2.8 used. I did some test shots, head shots of the SO and they are fine at f2.8. Looks like if it has enough to focus on, it does, but Dave -- Equine Photography www.caughtinmotion.com http://brooksinthecountry.blogspot.com/ Ontario Canada -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. !SIG:47cfe465241441572851132! -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: K10D focus test shot
On Mar 6, 2008, at 7:23, Steve Desjardins wrote: but now that I know I'll be sure to check and maybe even bracket focus a bit after checking the screen. Now that would be an interesting extended bracketing feature - focus bracketing! (only kinda kidding) -Charles -- Charles Robinson - [EMAIL PROTECTED] Minneapolis, MN http://charles.robinsontwins.org -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: K10D focus test shot
Charles Robinson wrote: On Mar 6, 2008, at 7:23, Steve Desjardins wrote: but now that I know I'll be sure to check and maybe even bracket focus a bit after checking the screen. Now that would be an interesting extended bracketing feature - focus bracketing! (only kinda kidding) Contax actually did that. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: K10D focus test shot
Did you use auto focus or manual focus. If you used auto focus all bets are off, the camera makes a decision. Now that could be tweaked in software, (I think anyway). If however you manually focused on the blue light and the yellow is in focus then you have a misaligned focusing screen, especially if your results are consistent. That is something that should never have left the factory. David J Brooks wrote: http://photo.net/photodb/photo?photo_id=7024435 Focus point is on the blue light. The yellow light is more in focus. When i focused on the yellow light, the one behind is in focus. F 2.8 used. I did some test shots, head shots of the SO and they are fine at f2.8. Looks like if it has enough to focus on, it does, but Dave -- Vote for Cthulhu. Why settle for a lesser evil... -- Dr. Jerry Pournelle -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
K10/100D focus test chart
I stumbled upon a test chart for k10/100D. There is nothing special about the test chart itself as it is a classic way of measuring the focus point and DOF etc. But this one has Pentax log on it, making it look like made by Pentax :-). I do not think Pentax made this, but it appears that you can just print this and assemble a scale box which might be handy for those interested in, or too clumsy or lazy to make these things. There is another guy who made not only a similar chart but a software to produce a graphic display of where the focus point is. Anyway, here are the templates (might take a while to download); For K100D: http://www.geocities.jp/pen_pen_pentax/focus/focustest100.pdf For K10D: http://www.geocities.jp/pen_pen_pentax/focus/focustest.pdf I have not examined this in detail on how to use it, i.e., if there is any set distance to place this etc. Ken -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
K10/100D focus test chart
I stumbled upon a test chart for k10/100D. Ken, I get a page advertising a drink of some kind, all in Konji ?? Walt -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: K10/100D focus test chart
On 2/27/07 4:07 PM, Walter Hamler, [EMAIL PROTECTED] wrote: Ken, I get a page advertising a drink of some kind, all in Konji ?? Hi Walt, Yeah, I realized that their (Yahoo!) server is busy or no service. It's midnight there and for some reason, geocity server there is often not available. What you are seeing is a message, saying try later :-). When it opens, it is a PDF which is a precise drawing to scale which you can cut (after printing) and assemble. If you really want to see it, you might try it tonight. I could open it last night but not this morning. Ken -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: K10/100D focus test chart
On Tue, 27 Feb 2007 16:07:54 -0500, Walter Hamler wrote I stumbled upon a test chart for k10/100D. Ken, I get a page advertising a drink of some kind, all in Konji ?? Walt I right clicked the link, save target as downloaded OK. John The information transmitted is intended only for the person to whom it is addressed and may contain confidential and/or privileged material. If you have received an email in error please notify Carmel College on [EMAIL PROTECTED] then delete all copies of it from your systems. Although Carmel College scans incoming and outgoing emails and email attachments for viruses we cannot guarantee a communication to be free of all viruses nor accept any responsibility for viruses. Although Carmel College monitors incoming and outgoing emails for inappropriate content, the college cannot be held responsible for the views or expressions of the author. The views expressed may not necessarily be those of Carmel College and Carmel College cannot be held responsible for any loss or injury resulting from the contents of a message. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
Re: K10/100D focus test chart
On 2/27/07 4:24 PM, K.Takeshita, [EMAIL PROTECTED] wrote: Ken, I get a page advertising a drink of some kind, all in Konji ?? Hi Walt, Yeah, I realized that their (Yahoo!) server is busy or no service. It's midnight there and for some reason, geocity server there is often not available. What you are seeing is a message, saying try later :-). When it opens, it is a PDF which is a precise drawing to scale which you can cut (after printing) and assemble. If you really want to see it, you might try it tonight. I could open it last night but not this morning. You can try from here, and open two separate PDFs from there. I could open them now. I save PDF files. http://www.geocities.jp/pen_pen_pentax/focus/ Ken -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
K10/100D focus test chart
Got it!! The right click on the link and save as did the trick. Walt -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
K10/100D focus test chart
I printed it out, cut it out, and assembled. My daughter, a kindergarten teacher, asked me what I was doing. I replied that I was working on Pentax Paper Doll cutouts. So, she proceeds to show me Canon Paper doll cutouts on the web! But these really were paper dolls. BTW, the focus checker worked as advertised and my K10 is perfect with both the 18~55 and the 50~200, Didn't test the FE Zoom ...what't would be the point! :-) Walt -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
