Re: [Elphel-support] Elphel 353 - Question about Focus
Hi, *Lens:* E3Z4518CS-MPIR We haven't been able to get the focus to show the cards as sharp that with the Sanyo cameras. The cards are a 124cm from the camera, and with the Sanyo ones we are using a Pentax 5-50mm lens. Any advice or recommendation you may have to help us out with this project will be really appreciated. When the focus is the best - is the focusing ring at its extreme position? If yes: a. ideally you need to increase the sensor's distance from the lens by adjusting the sensor's plate position (1-2 mm probably) in the front end. or b. decrease the working focal length (wider field of view) - rotate the ring towards W until you get the best focus. c. you can also try closing the iris a little to increase the depth of field. If no, then a better lens should be tried probably. What's the image quality? frame dimensions? Best regards, Oleg Dzhimiev Electronics Engineer phone: +1 801 783 x124 Elphel, Inc. ___ Support-list mailing list Support-list@support.elphel.com http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com
[Elphel-support] Elphel 353 - Question about Focus
Hello Elphel,* Model*: 353 *Camera release:* 8.2.15 *Sourcecode:* elphel353-8.2.15.tar.gz GNU GPL V3, FDL V1.3, GPL V2 Licenses *Camera Serial Number: *00:0E:64:08:1C:FF *Lens:* E3Z4518CS-MPIR Just wondering if I can get some advice from you guys. We are working in a project to replace our old///Sanyo/ VCC-/HD2100/ cameras, with Elphel ones, so far we really really like these cameras. But we had have a hard time focusing our top shot, in the next image you will appreciate the Elphel on the left and the Sanyo on the right: We haven't been able to get the focus to show the cards as sharp that with the Sanyo cameras. The cards are a 124cm from the camera, and with the Sanyo ones we are using a Pentax 5-50mm lens. Any advice or recommendation you may have to help us out with this project will be really appreciated. Thanks in advance for your help. Regards. -- ___ Support-list mailing list Support-list@support.elphel.com http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com
Re: [Elphel-support] Elphel 353 - Question about Focus
Hi Oleg, My comments below. Thank you. On 01/21/2015 01:54 PM, Oleg wrote: Hi, *Lens:* E3Z4518CS-MPIR We haven't been able to get the focus to show the cards as sharp that with the Sanyo cameras. The cards are a 124cm from the camera, and with the Sanyo ones we are using a Pentax 5-50mm lens. Any advice or recommendation you may have to help us out with this project will be really appreciated. When the focus is the best - is the focusing ring at its extreme position? /At the best it is not at the extreme position./ If yes: a. ideally you need to increase the sensor's distance from the lens by adjusting the sensor's plate position (1-2 mm probably) in the front end. or b. decrease the working focal length (wider field of view) - rotate the ring towards W until you get the best focus. c. you can also try closing the iris a little to increase the depth of field. If no, then a better lens should be tried probably. What's the image quality? /JPEG 92%/ frame dimensions? /1280x720 - 25fps/ Best regards, Oleg Dzhimiev Electronics Engineer phone: +1 801 783 x124 Elphel, Inc. -- ___ Support-list mailing list Support-list@support.elphel.com http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com
Re: [Elphel-support] Elphel 353 - Question about Focus
Oleg, I will give another try to your suggestions. But in case that we don't find a solution, what lens willl you recommend for this? Thanks in advance. On 01/21/2015 01:54 PM, Oleg wrote: Hi, *Lens:* E3Z4518CS-MPIR We haven't been able to get the focus to show the cards as sharp that with the Sanyo cameras. The cards are a 124cm from the camera, and with the Sanyo ones we are using a Pentax 5-50mm lens. Any advice or recommendation you may have to help us out with this project will be really appreciated. When the focus is the best - is the focusing ring at its extreme position? If yes: a. ideally you need to increase the sensor's distance from the lens by adjusting the sensor's plate position (1-2 mm probably) in the front end. or b. decrease the working focal length (wider field of view) - rotate the ring towards W until you get the best focus. c. you can also try closing the iris a little to increase the depth of field. If no, then a better lens should be tried probably. What's the image quality? frame dimensions? Best regards, Oleg Dzhimiev Electronics Engineer phone: +1 801 783 x124 Elphel, Inc. -- ___ Support-list mailing list Support-list@support.elphel.com http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com
Re: [Elphel-support] Elphel 353 - Question about Focus
Hello David, Do you use decimation or just a smaller window to reduce the frame size to 1280x720? Decimation on all Bayer mosaic sensors is not optimal, it is designed mostly for a quick-preview or viewfinder mode. Aptina datasheet has a full explanation, but in short, it is not possible to throw away each other pixel - instead of RGRGRGRG line you will get RG--RG--, so there will be two-pixel gaps, not one pixel ones as in the case of a pure monochrome sensor. Binning will produce the similar results So I would recommend using window, not decimation/binning, and if you anyway use only 1280x720 you may get better results with a 1/3 or even a 1/4 lens. The full frame will have dark image outside of the center area, but it may be easier to get higher resolution in the center you need. Also fixed-focal length lenses generally produce better image than varifocal ones, so you may use the current lens to find the optimal focal length and then put a fixed-focus one instead. There are many lenses 1/3 and 1/4 format we can try, including M12 ones with adapter. Andrey ___ Support-list mailing list Support-list@support.elphel.com http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com
