Infrared lenses need to be carefully chosen as some lens/camera combinations create a ‘hotsp[ot’ or lighter area in the centre of the frame which is distracting and often hard to correct in Photoshop. The intensity of the hotspot can change with the aperture used – often smaller apertures (f5.6 and smaller can be the worst affected. Often, the lenses which perform worst in this regard are the more modern, multi-coated (and expensive) ones, while older, simpler lenses seem to do better. However, there are no hard and fast rules, its down to trial and error.
Here is my infrared lenses “no hotspot” lens list (all on a Sony alpha 6000, 720nm filter and Kolarivison anti-glare option). Canon fit lens all mounted on a Fotodiox Pro EF-Sny(E) Smart AF Adaptor. (Which is not that smart and doesn’t really work in AF – so I use manual focus.)
Sony 10-18 f4 – a great wide angle zoom. Very small and full autofocus. (I found the kit lens supplied – Sony 18-50 f3.5 – 5.6 – to be awful for ir – with serious hotspots at all f-stops.)
Lensbaby Velvet 56mm f1.6 (Canon fit) – love this lens both for infrared and regular colour work. Its an old school, heavy, glass manual lens and its party trick is to become progressivley soft-focussed from around f4 until at f1.6 its creates a very soft image with a tiny sharp plane of focus.
Canon 24-105 f4 L (Canon fit) – please note I have the mark I version which is now superceded by the mark II version and which I have not tested for IR. Sharp across the range with no hotspots. I get best results with manual focus and image stabilization turned off.
Lensbaby Composer + Double Glass Optic (Canon fit) – original version with the magnetic f stop rings. I have read in a couple of reviews that all Lensbaby combinations are great for IR with no serious hotspots.
Canon EF 100 f2.8 L macro (Canon Fit) – only for close up work with flash in the studio but no hotspots.
All these are great infrared lenses and I hope this is helpful to anyone looking to try infrared photography.