Is it possible to decrease focus distance to 3-4 centimeters on fixed-focus OV2640 camera modules which sell with Chinese ESP-32 CAM or M5Stack ESP32 CAM?
They are set up to infinite focus out of the box.
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\$\begingroup\$ @Transistor, it's hard to find specs on camera module. There is datasheets for CMOS sensor waveshare.com/wiki/File:Ov2640_ds_1.8_.pdf but not lens. I think only one way - check it manually if you have one \$\endgroup\$– br.Sep 12, 2019 at 22:30
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\$\begingroup\$ Add approx. +25 - 30 dioptre lens \$\endgroup\$– NMFSep 12, 2019 at 23:26
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\$\begingroup\$ @NMF, 30 diopters is ~8x I think? \$\endgroup\$– br.Sep 13, 2019 at 8:36
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1\$\begingroup\$ @br. Magnification is relative and depends on the rest of the optics, but for a hand magnifier, yes, 30D would be of the order of 8x magnification \$\endgroup\$– NMFSep 13, 2019 at 14:36
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2 Answers
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The existing lens is adjustable, you just need to turn the knurled ring around the lens, as shown here:
See whether that lets you focus close enough. If not, you might be able to find a different lens in the same kind of holder.
answered Sep 12, 2019 at 23:55
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\$\begingroup\$ Yes, I know that it can be screwed up and down, but what mininum distantion without external lens? \$\endgroup\$– br.Sep 13, 2019 at 8:01
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\$\begingroup\$ I don't know. What did you get when you tried it? \$\endgroup\$ Sep 13, 2019 at 10:52
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\$\begingroup\$ I have no module in hands. I want to buy one but can't find such information. Hope that some DIYers have this. \$\endgroup\$– br.Sep 13, 2019 at 12:33
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I tried it on the OV2640 camera that came with my ESP32-CAM. It has some kind of glue on it that makes it very hard to turn! I have read that you can take a VERY sharp small blade and cut through the translucent glue that are locking the threads and then be able to focus it manually.
But I do not know what the closest possible distance is however. But the closer the object is to the lens, the further away the CMOS sensor has to be. So if there is not enough threads on the lens holder, you could create an extension, somehow, that would enable focusing on closer objects.
BTW, you can also completely unscrew the lens and you should then be able to remove the IR filter so you can do "night vision" with IR LEDs for illumination.
