Infrared performance of Fujifilm X Mount LensesThese test images were taken on a modified infrared only Fujifilm X-E1 with a Schott Glass internal 830nm infrared pass filter. They show how well each lens works in the infrared only spectrum where problems often occur with hot-spots - bright areas in the centre of the frame.
Hot-spots have several causes. Some are caused by internal reflections inside the lens elements or between the infrared pass filter and the rear element of the lens. In visible light these internal reflections are reduced by 1/4 wave multi coatings on the elements but these coatings are ineffective at wavelengths beyond 800nm and can sometimes cause increased internal reflections at infrared wavelengths. Others can be caused by internal reflections off the aperture blades of internal lens mechanisms - again the anti reflection coatings may not be fully effective at IR wavelengths. A third type is caused by the lens multi coating transmitting variable amounts of IR depending on the angle of incidence - these most often effect very wide angle lenses.
Generally hot-spots are worst at smaller apertures (larger f numbers). However softness caused by diffraction in infrared generally means that the optimum balance between depth of field and sharpness is between f/8 and f/11 for and infrared only camera and between f/5.6 and f/8 for a false colour infrared camera.
Whilst these tests do not guarantee the lens performance on a false colour infrared camera with a lower pass filter of 740nm, in my experience lenses that perform well in pure infrared generally perform well in false colour. However they do not necessarily show how well the lens will perform on an unmodified camera with an infrared filter mounted externally as the external filter can also be the cause of hotspots.
Please note that the conclusions are my own subjective opinion of how well each lens performs in infrared and should only be used for guidance. All images were shot as RAW files and converted into JPGs using Adobe Lightroom 5.4 using the Adobe Standard profile. The test images are intended to show the presence or absence of hot-spots rather than overall sharpness and are all scaled to 1000px wide to save bandwidth.
For those who want the quick answer my favourite lenses for IR shooting are the XF14mm and XF35mm primes and the XF18-135 WR Zoom - both fantastic performers in infrared!
Fujinon XF Prime Lenses
XF 14mm f/2.8 R Excellent IR performance at all aperturesThe 14mm prime is a superb performer in IR at all apertures and never exhibits hot-spots. As expected it shows some edge softness at f/11 and above but is extremely sharp wide open.
XF 18mm f/2 R Not suitable for IRThe older 18mm prime does not perform well in infrared. It is very soft at f/2 and has increasingly bad hot-spots at all other apertures.
|18mm at f/2|
|18mm at f/4|
|18mm at f/8|
|18mm at f/16|
XF 23mm f/1.4 R Excellent IR performance at all aperturesLike the 14mm, the 23mm prime is very well behaved in IR showing no hot-spots at any aperture. It is sharpest at around f/5.6 with diffraction well controlled at f/16
|23mm at f/1.4|
|23mm at f/5.6|
|23mm at f/8|
|23mm at f/16|
XF 27mm f/2.8 - Only usable at f/2.8 in IR
(images to follow)
XF 35mm f/1.4 R - Good IR performance at f/11 and belowThe older 35mm prime is another good infrared performer. It has a very slight hot-spot at f16 but at all wider apertures it shows no hot-spot and excellent sharpness even at f/1.4
|35mm at f/1.4|
|35mm at f/2.8|
|35mm at f/8|
|35mm at f/16|
XF 56mm f/1.2 R - Only usable at f/2.8 in IRSadly the 56mm prime, a stunning lens in visible light, does not fare so well in IR. Wide open it is quite soft, sharpening up nicely at f/2.8 with no hot-spot. However by f/4 a hot-spot is clearly visible which worsens as you stop down. The APD version of this lens has also been tested by Bertrand T and has the same IR performance as the standard version.
|56mm at f/1.2|
|56mm at f/2.8|
|56mm at f/5.6|
|56mm at f/16|
XF 60mm f/2.4 R Macro - Only usable wide open in IRThe macro 60mm is sharp wide open and shows no hot-spot. However as soon as you stop down the hot-spot starts to appear rendering it unusable at f/5.6 and above.
|60mm at f/2.4|
|60mm at f/4|
|60mm at f/8|
|60mm at f/22|
Fujinon XF Zoom Lenses
XF 10-24mm f/4-5.6 R OIS - Not suitable for IRThe 10-24mm wide-angle zoom is another excellent visible light lens that doesn't work so well in infrared. Between 10mm and 20mm it shows a soft but visible hot-spot at all apertures, only giving useable results wide open at 24mm, with the hot-spot returning as soon as you stop down.
|10-24 at 10mm f/4|
|10-24 at 10mm f/11|
|10-24 at 18mm f/5.6|
|10-24 at 18mm f/11|
|10-24 at 24mm f/5.6|
|10-24 at 24mm f/11|
XF 18-55mm f/2.8-4 R LM OIS - Not suitable for IRLike the 10-24mm, the 18-55mm standard range zoom is not a lens to use in infrared. At 18mm a hot-spot is visible at all apertures. At 35mm it is just about usable wide open but the hot-spot appears as soon as you stop down. At 55mm it is again fine at f/4 but exhibits a hot-spot at all other apertures.
|18-55 at 18mm f/2.8|
|18-55 at 18mm f/11|
|18-55 at 35mm f/3.6|
|18-55 at 35mm f/11|
|18-55 at 55mm f/4|
|18-55 at 55mm f/16|
XF 55-200mm f/3.5-4.8 LM OIS - Usable below f/8 at all focal lengthsAfter disappointing results from the 10-24mm and 18-55mm zooms this lens was a real surprise. At all focal lengths it is free of hot-spots wide open and generally useable up to f/8. Beyond f/8 a gentle soft-spot appears in the 55mm to 100mm range, but this is markedly reduced at longer focal lengths and by 200mm the lens performs well at all apertures.
|55-200 at 55mm f/3.5|
|55-200 at 55mm f/8|
|55-200 at 100mm f/4|
|55-200 at 100mm f/8|
|55-200 at 200mm f/4.8|
|55-200 at 200mm f/11|
XF 18-135 f/3.5-5.6 R LM OIS WR - Excellent performer at all focal lengthsAfter preliminary testings with a prototype 18-135 I have now been able to shoot extensively with a production version of this lens and can confirm that it is a superb all round performer in Infrared with practically no evidence of hot-spots at any focal length or aperture below f/11 and only the slightest hot-spot appearing at f/22 @ 135mm. Sample images coming soon.
XF16-55/2.8 R LM WR - Mixed reports from users - caution advised...
XF 50-140/2.8 R LM OIS WR - Excellent performer at all focal lengthsTested by Bertrand T - Fine across the range at all apertures
Fujinon XC Zoom Lenses
XC 16-50mm f/3.5-5.6 OIS - Mixed reports from users - caution advised...
I have not yet had a chance to test this lens myself but I have had varying reports from users. Some say that it performs much the same as the XF 55-200 zoom and is useable below f/8 at all focal lengths but Vic C tells me "Forget the 16-50 mm XC it doesn't focus Ir and it has a hotspot at all apertures all FLs..."
XC 50-230mm f/4.5-6.7 OIS - Not yet tested
Zeiss Touit X-mount Lenses
Touit 1.8/32 - Not yet tested
Touit 2.8/12 - Not yet tested
Touit 50/2.8 Macro - Usable below f/8 at all focal lengthsTested by Bertrand T - Perfectly fine until f/5.6, barely visible hot-spot at f/8 (still very usable aperture) and then severe worsening.
Samyang X-mount Lenses
Samyang 8/2.8 fisheye: - Mixed reports from users - caution advised...
Tested by Bertrand T - Fine at all apertures...
Also tested by Gary - only really usable wide open...
Also tested by Gary - only really usable wide open...