Guest Author -- Niek Haak
Part One :
Five years ago Sony started offering a Nightshot mode on certain Cybershot digicams. In Nightshot mode the internal IR blocking filter is temporarily moved aside, out of the light path to the sensor, enabling handheld infrared photography with an off-the-shelf digital camera. Nightshot mode, despite its limitations, made these Cybershot models very popular among IR photographers. The last Sony digicams to offer this mode, the DSC-F828 and DSC-V3, disappeared from the market some time ago.
Now there is a new Nightshot kid on the block, the DSC-H9. Does it offer the same opportunities for infrared photography? The DSC-H9 is quite a change from the previous models with Nightshot. It has a bigger zoom range, image stabilizer, better/faster autofocus, big and bright flip LCD, smaller overall size and ... a much smaller image sensor.
I am currently using a DSC-F717 for my IR photography; last year I removed the internal blocking filter to bypass the Nighshot limitations. This IR modification makes the 717 a great IR digicam, but there is always room for improvement. The lack of true wide angle zoom on the 7x7s requires the use of a bulky converter to get to 28 mm (the newer 828 and V3 include the 28 mm zoom setting), and the LCD is small and has its limitations. On paper the DSC-H9 looks great: it has a wide angle zoom (at 31 mm a bit less than I would like, but better than the 38 mm minimum on the DSC-F707/717) and packs a lot of punch into a small package.
Nightshot Limitations With the DSC-H9 in Nightshot mode, the only setting one can adjust is the amount of megapixels that are captured; the rest seems to be fully automatic. I did most of my testing in 5 MP instead of 8 MP mode (easier to compare results with my Sony 717, and maybe better image quality?). I set the camera at 80 or 100 ISO before testing, but I'm not sure yet if it retains that setting in Nightshot mode. Nightshot always works with full open aperture (variable from f/2.7 to f/4.5) and a maximum 1/30 sec shutter speed. The slow shutter speed is less a problem because the image stabilizer (Steadyshot) helps, at least for static scenes like landscapes. Although it is not completely reliable at these shutter speeds, I got acceptable images even at full 465 mm zoom in Nightshot mode.
This is a huge improvement compared to older Cybershot models, where anything above 50 mm equivalent or so in Nightshot mode requires a tripod. Of course a modded DSC-F717 is better, but that is not an off-the-shelf option. The other limitation is that - like previous Nightshot incarnations - in normal daylight, ND filters are required to prevent overexposure at 1/30 sec. (check Jerry's excellent article about Nightshot mode in the Beginner’s Section).
The Nightshot Switch There is a way to bypass the Nightshot limitations, by using an 'in-between' setting for the Nightshot switch. This removes the blocking filter with the camera still in the mode as set with the mode dial. Just a slight touch will switch back to full Nightshot mode or normal camera mode: one has to fiddle with the switch before every picture. Also, there is a fuzzy black border in the lower part of the image when using this trick. The border is caused by the frame of the IR blocking filter that is not yet completely out of the optical path. With this setting, just looking at the LCD shows that the camera uses both infrared and normal light. With the blocking filter removed in normal mode I could not set the white balance (Aperture priority mode and R72 filter); the red/purple tint seems to be outside the possible WB range. One can choose a black-and-white mode for BW IR pictures directly out of the camera, but for experimenting with color infrared the H9 does not look promising.
Using filters For best results, an infrared filter is necessary (plus ND filters when using Nightshot mode). We run into some trouble here ... There is no official way to mount filters on the H9, except for the non-standard 74 mm filter thread on the Sony lens adapter. Obviously, there are no 74 mm infrared filters on the market. Stepdown rings that mount on the Sony lens adapter are available, but only the 72 mm size seems safe for mounting a filter. Pemaraal is working on a telescoping adapter that should work with smaller filters; it looks very nice but is not yet available.
When hand holding one filter directly in front of the H9 lens, 58 mm filter size is OK: even at maximum wide angle setting there is no vignetting, as long as you keep your fingers in the right position ;-) I started experimenting with a Cokin P filter holder with resin filters; it works, but it is bulky compared to the H9. Mounting a stack of round filters (infrared + ND4 + ND8, as with previous Nightshot models) is not an easy solution either. Even with the new Pemaraal adapter, three 58 mm filters would give strong vignetting at wide angle, and a stack of bigger filters would be heavy and expensive. So, for the infrared filter some kind of compromise or workaround will be necessary.
Conclusion: There are some problems, but overall the H9 looks promising.
In Part 2 we take a closer look at: suitable infrared filters, required Post Processing, and image quality issues for infrared photography (compared to other options like the older DSC-F717).
Here is one of my early results (using very little image processing).
You can find some IR examples in my DSC-H9 test gallery.
H9 IR Test Gallery
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