Infrared and the X Pro 1

The unmodified X Pro 1 is sensitive enough to IR for handheld shooting with a 720nm filter, a short lens, a steady hand and cranked up ISOs. Here is one of the my favourite examples: 


1/20s, F2.5 at ISO 1600 with the 18 mm lens. I took this photograph over a year ago and have had a bit of success since. I like this one too.


I managed to lose the Exif, but for this one I used a tripod so I am guessing I stopped down a bit. What I don’t like about this photograph is that when you look closely you can see a circular zone of increased brightness. It is noticeable on the trunk. It is a dreaded infrared hotspot. They are very unpredictable - sometimes you get them sometimes you don’t, but I have experienced hotspots with the 18mm, 35mm and 60mm fuji lenses. With the 60mm it is hard not to get a hotspot. I have seen reports of no hotspots on the 35 and only hotspots on the 18 when stopped down. This is not my experience. Hotspots are least common on the 35, but they are still present. Hotspots are common on the 18 even when opened up. Here is an example where I managed to use the nuisance hotspot for creative effect:


This photograph taken using the the 35mm has a  pronounced hotspot even fairly wide open at F 2.8.

I find IR photography quite hit and miss - flare is more pronounced, noise reduction for high ISO handhold shots can destroy the natural feel of the shot…..but when IR shots work they can be quite magical. I don’t want the occasional bit of magic to be messed up by a hotspot. I have begun a little quest to find the best lens for IR with the xpro. I want to be able to have the option to hand hold so it has to be fairly wide and fast. A logical place to start may have been the 14mm or the new 12mm zeiss. I ruled out both of the logical choices as they are a bit to wide, a bit too pricey and a bit too large to have hanging around in my bag for occasional use….so instead I went the legacy route…with a Nikon 24mm F2.0 adapted using a Metabones speedbooster. I went with with a 24mm so that it can do double duty for IR shooting and give me a bit more width than the 28mm equivalent of the Fuji 18mm in case I need it for regular shooting in visible light.

There a some reports of hotspots with the Nikon 24mm F2.0 but according to these reports they are only a problem at F8. I should be able to avoid F8. Also the Speedbooster increases the light gathering capability of the lens so that it behaves like a F1.4. This should be a real advantage for handheld shooting.

So far I have not done that much with the 24mm F2.0, but I have yet to see a hotspot and am happy with results when stopped down. Here is a example:

Kalamalka Sky

This is an IR long exposure of almost 2 min. I used an ND filter along with the IR filter to achieve such a long exposure in full sun. I didn’t record the aperture was but it was somewhere between 5.6 and 11. 

Observations so far:

— Wide open the 18mm fuji has better image quality than the 24mm nikon. Both are quite sharp in the center and quite soft in the corners, but corner softness is more pronounced on the Nikon and it has noticeably less contrast across the frame. When shooting at high ISO settings for handheld IR the loss of contrast using the Nikon is hard to recover in post as big tweaks in exposure accentuate the noise. Going forward I am thinking that the 18mm fuji will be best for handheld shooting and the Nikon will best for work on a tripod. It would have been nice to have one lens for that is contrasty wide open and isn’t susceptible to hotspots when stopped down…..but perhaps that is not going to be possible.

Update Sept 1 2013: See later post. By changing the way that I process the lower contrast files produced by the 24mm lens I can increase contrast without reducing noise. I think this lens will work both opened up for handheld shooting and stopped down for shooting on a tripod. 

— You need to watch out for flare with IR. The sun was just out of frame with this image. No lens hood, wide angle lens….this is to be expected.

— The field of view is not a true 24mm full frame equivalent. The Speedbooster does not record the complete full frame image. It crops it to the tune of about 7%.

— The Speedbooster is filled with glass and is very dense compared to regular adapters that just act as spacers. While the 24 f2 feels light and looks miniature on my D700 with the Speedbooster it looks large and feels heavy on the Xpro1.

— I use manual focus a lot with my fujis and always found focus by wire to be acceptable. After using the a real manual focus lens I can now see why people don’t like the focus by wire. The manual focus lens feels much nicer and is much faster to focus manually.

  1. gearramblings posted this