H50 is very infrared responsive in normal modes

I have been using my H50 a bit this week, and testing its IR performance, which is what I bought it for. The one I have is modified so that the nightshot switch only flips up the internal hot mirror, but does not turn on the nightshot mode and it works great for IR (and should have no effect on its performance when in 'color' modes). I have also noticed that even when the hot mirror is down the camera picks up a ton of infrared. I wasn't sure that about what I was seeing so I did some testing, with a standard TV remote facing the camera. I found that the camera can see the signals from the remote even with the hot mirror down, but noticeably less than with the mirror up (nightshot). I then added a Tiffen hot mirror with the camera in normal mode and the IR was almost gone. If I use the same tv remote with my a350 or v3 there is nearly no light picked up from the TV remote pointed at the camera.

I find it interesting that Sony put such a weak hot mirror in the h50. It does well for the reason I bought it, but if I really wanted to use it for color photography I would use a hot mirror. It picks up way more IR than any other camera I have tried.

I haven't taken any sample pics of my finding yet, maybe soon, but I was wondering if any other H50 owners have seen this?

Greg
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http://www.flickr.com/photos/gkemp/

Every digital camera i ever had could see the infra led on tv remotes.

Yes, but what I am saying is the h50 is MUCH more responsive than other camera, its not just a little bit, the difference is obvious enough that when shooting outside in color I can see the infrared in the LCD live view and in the pics I take. It should not be that way.

Greg
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http://www.flickr.com/photos/gkemp/

difficult to draw any conclusions if you don't know the transmission curve of the hot mirror. Usually these internal hot mirrors have a pretty steep cutoff value, maybe this one has the same but shifted 20nm or so to the infrared range. Depending on your remote LED wavelength that could make a huge difference, and it doesn't need to impact normal color.

Does the H50 have problems rendering sunlit plants, leaves etc? Too blurry plant details and strange colors would hint at too much IR seeping through, probably as a result of a weak (thin?) hot mirror.

I think it is impacting normal color somewhat. I was taking pics of a sunset the other day and there was so much pinkish light (likely infrared) coming in that I opted not to use the H50 for color. My a350 has a very thick hot mirror plate in it which looks like 2 layers of glass glued together and you can tell it is well coated.

That same TV remote I tested the H50 with cannot even make enough IR for my a350 to see it. My a100 does pic up some IR light as well, but its only noticeable when there is a lot of contrast and strong sunlight, such as a forest with a beam of sunlight reflecting off of a puddle, I could see a pink fringe (that I found was not CA) all around the reflection. I was really surprised when I took out the H50 to shoot color, but maybe I am just comparing SLR's to point and shoots since I do not normally shoot difficult things like sunsets with anything but my a100/a350. I don't really have a good reference of my own for what to expect when pointing my H50 at the sun without any extra filtration

Greg
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http://www.flickr.com/photos/gkemp/

Gregory Kemp said:

I think it is impacting normal color somewhat. I was taking pics of
a sunset the other day and there was so much pinkish light (likely
infrared) coming in that I opted not to use the H50 for color. My
a350 has a very thick hot mirror plate in it which looks like 2
layers of glass glued together and you can tell it is well coated.

Click to expand...

in DSLRs this sandwich is usually not just a hot mirror but yes, they are much thicker. Often there is an interference hotmirror (looks like a strongly colored coating) and an absorption hot mirror (glass has a bit cyan-greenish color). The hot mirror in older digicams was often 1-3mm thick; in recent digicams it is sometimes very thin (like 0.5mm), and despite better technology maybe less effective.

Gregory Kemp said:

I was really surprised when I took out the
H50 to shoot color, but maybe I am just comparing SLR's to point and
shoots since I do not normally shoot difficult things like sunsets
with anything but my a100/a350.

Click to expand...

I can only compare my Sony digicams with Canon DSLRs (300D and 450D), and the DSLRs are far less sensitive to IR, out-of-the-box. Canon is known for using very steep hot mirrors in their DSLRs, IR transmission in the 450D is close to zero.

As long as the IR is just a small part of the near-IR around 700nm, I don't think it needs to impact color rendering. If the filter is weak and transmits more near-IR (like 700-800nm), it will probably impact color quality (and sharpness, under certain conditions). I remember reading some remarks about strange colors with the H50 for grass etc., but difficult to say if that is because of IR contamination or simply because of the in-camera processing. And with very high light levels like when pointing directly at/near the sun, you get other problems besides IR that can impact color (happens with my DSLRs as well).