Sony DSC-V3 for daytime infrared

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All this effort just to cop a peek through women's clothes? Why not use the old-fashioned methods?

Best regards, Spehro Pefhany

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Nice, Spehro - - you and Sony think alike.

Two optical solutions come to mind. One is to add an external IR filter. You may find once you filter the light, you don't have an aperture problem. The other is to use a neutral density filter. A polarizer might have enough light loss. I suspect the IR filter is the best solution.

While I haven't tried to photograph women through their clothing, i.e. you intended application, I did buy an IR filter from

for use with IR film.

It looks like the smallest R72 they sell is 49mm, so you will probably need a step up (or is it down) ring. These are quite cheap, but you need to read the literature carefully to figure out which direction it works.

Yes, that is the only way that avoids tearing into the electronics of the camera. Typically they find an R72, plus an ND8 and an ND4 work to bring the IR exposure down to a useful value despite the forced camera settings in Nightshot. See

for various combinations of filters and corresponding results. But that pretty well limits the camera to tripod use. The improvement you get with the electronic hack is full control for handheld use rather than being stuck with 1/30 @ f/2.8. With the proposed mod, the camera can then be restored to normal color response just by cycling the Nightshot button - - the best of both worlds, and worth going to some trouble, I feel.

I understand the DSC-V3 requires an extension tube with a proprietary 47mm thread at the camera end to hold the filter since the lens pokes out when zooming. I've seen two versions of the adapter tube, for either 52 mm or 58 mm filters, and expect to use an existing 58mm R72 that I bought long ago for my Nikon Coolpix 950. The winter white rendering of green sunlit foliage by an IR camera is an extraordinary effect - - something every digital camera ought to be equipped to do.

Fortunately, Sony publishes a Service Manual and in the Level 3 section, most of the questions below are answered there. The H-Bridge driver is an LB1938T-TLM-E and I found a full data sheet by Sanyo just doing a Google search for LB1938T. The camera is powered by a 3.6V Li-Ion cell, but there's a large DC-DC converter system in there that produces a variety of voltages, one of which is +5V which runs this chip, among others.

One large question that remains is, what will happen if I drive the desired input of this chip to +5 while it's connected to an output pin of the microprocessor? Presumably both inputs are held low in "standby" between programmed actuations of the filter motor, so driving one high is potentially a contentious operation. Are microprocessor outputs typically "3-state"? It they aren't, will the output driver in the microprocessor survive this abuse? The H-Driver chip will see an input high if it can be pulled up to +2V, so I would like to add a resistor in series with the switch in the effort to be "kind" to the microprocessor, hoping it will live a long, eventful life. If the outputs are not "3-state" then what typical output resistance at "low" can I expect to encounter from a typical microprocessor in this battery portable application?

Thanks,

Chuck

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Ok, I got my hands on a DSC-V3 that had a bad lens assembly. The previous owner really tore into the lens assembly, which is now useless. But it gave me the chance to look at the mechanics of the "Nightshot" function. Reading Macona's claim and after reading the article on modifying a DSC-717 at

I wonder now how he is managing to focus the camera correctly since the hot mirror stage assembly on the V3 is very similar to the 717's and it does state that without it, the camera optical circuit will not compensate for the refractive loss of the hot mirror while in normal modes, making focusing to infinity impossible. It's placement is between the lens and the CCD, just like the 717's.

At first, I thought it would be easiest to open the circuit with a small switch ( based on the fact that I do not have the schematic and, like you, I had no way to ID the SO-8 H-bridge chip or the pinouts...lazy, I guess LOL). Activate the Nighshot mode, open the switch on the solenoid's circuit, then cycle to the normal mode, which would leave the hot mirror in the Nightshot position. This should allow IR shooting in the full color modes and with full aperture/ shutter control. So I would have thought...until I read

: ===================================================================================== The original hot mirror (left) is a small piece of optical glass, size

11 x 13 x 1.2 mm. I replaced it with a special optical window that transmits light from +/- 300 to 2000 nm, instead of just 400-700 nm for the standard Sony hot mirror. After modification the F717 will record images with light from +/- 350 - 1100 nm (the sensor/glass combination will not work outside this range). This range includes most of the near- infrared spectrum.

It is VERY important to replace the hot mirror with another optical window with the same dimensions (especially thickness, the tolerance is about 0.02 mm) and refraction index, otherwide the camera will no longer be able to focus (especially at infinity /wideangle). If you do not replace the original hot mirror with anything, the camera will only focus in Nightshot mode (this is because the optical window is part of the optical system).

You can try to make your own window from a microscope slide or other piece of optical glass grinded to specifications, but it will require a lot of trial and error because the window must be perfectly flat. If it is too thick, it will probably not fit in the stage (maximum thickness is about 1.3 mm). Note: microscope slides have no AR coating, using uncoated glass will cause extra reflection / hotspot problems. =====================================================================================

So technically, applying the correct voltage to actuate that solenoid or my supposed open circuit solution will move the hot mirror out of the way, but it will not compensate for focusing. RATS! Macona makes only one mention on focusing on another post:

===================================================================================== Two days ago I also modded my Sony DSC-V3. This camera has the built in nightshot but it is limited. It only functions in standard and "P" modes as well as movie mode. Also you can not use the flash in this mode. I took apart the camera (much further than I had to.) and found how the night shot system worked. It is simply that the IR filter is on a solenoid. The camera moves the filter out of the way in night and back in normal. Seeing as there is proabably no way to get into the firmware there had to be a hardware hack. I found that the solenoid is controlled with a little surface mount (SO-8) H-bridge chip. I installed a tiny swithc that sends a pulse to the chip which manually moves the filter out of the way. Just cycle throught the nightshot modes to return to normal. Now I can use the camera as a normal color digicam and full IR mode by placing IR pass filter over the lens and flash. Or even better use the hotshoe or ACC plug to control an external IR flash. Only problem I have had is that the camera has a hard time focusing at full wide angle. Fix is just zoom in a bit. ================================================================================================= I am more prone to trust in the Niek Haak article on the 717 than Macona's zoom focusing fix. And most all IR mods I have seen replace the hot mirror in one way or another.

If you are able to find a viable solution, I will commend you. But for now, I can deal with the slow shutter speeds and the ND8, ND4, CPL combo with a 950 nm filter.

In the mean time, I got a V3 I can experiment with ( possibly adapting a manual focus SLR lens ) to see what I come up with!

Laters!