im not sure about the tokina..but u can ask the others.
with a 77mm IR filter mounted on the front..i usually zoom in slightly to ard 12mm....
with a tokina...u might be shooting at ard 14mm if u zoom in a little. maybe the tokina users can say something about this. :think:
i do this to prevent vignetting at the corners.
everyone got their own style / workflow....so try out different settings!
im not sure about the tokina..but u can ask the others.
with a 77mm IR filter mounted on the front..i usually zoom in slightly to ard 12mm....
with a tokina...u might be shooting at ard 14mm if u zoom in a little. maybe the tokina users can say something about this. :think:
i do this to prevent vignetting at the corners.
everyone got their own style / workflow....so try out different settings!
I'm using the Tokina 12-24mm, but I experience hot spot even at f/4, so I wanted to ask about the Sigma 10-20mm, and it's listed in the bad lenses for IR...sigh.
So, you were saying when you use ur Sigma 10-20mm at f/8, and above, such as f/5.6, you didn't experience any hot spot???
I'm using the Tokina 12-24mm, but I experience hot spot even at f/4, so I wanted to ask about the Sigma 10-20mm, and it's listed in the bad lenses for IR...sigh.
So, you were saying when you use ur Sigma 10-20mm at f/8, and above, such as f/5.6, you didn't experience any hot spot???
So if you use a modified camera, then hot spots are not likely to appear since you won't use long exposures?
If so, then does this mean that those lens listed as 'bad lens for IR' may potentially be usable on modified cameras? (eg Tokina 12-24mm f4 was specifically listed as bad)
So if you use a modified camera, then hot spots are not likely to appear since you won't use long exposures?
If so, then does this mean that those lens listed as 'bad lens for IR' may potentially be usable on modified cameras? (eg Tokina 12-24mm f4 was specifically listed as bad)
I remember a guru telling me hot spots are not caused by long exposure but refraction of the lenses. You should be able to avoid it when you stop down but the price is the shallower DOF.
I remember a guru telling me hot spots are not caused by long exposure but refraction of the lenses. You should be able to avoid it when you stop down but the price is the shallower DOF.
Here are some IR shots taken today with the Sigma 10-20mm.
1. f/8. No hotspot. But note that it is very cloudy
2. f/8. Hot spot is seen in the centre. Here, the sun was starting to come out.
3. f/5.6. Hotspot is less severe here with this aperture setting. Lens hood is mounted.
It was generally cloudy today. I'm pretty sure that the hotspots will be more severe on a bright sunny day. Hence it is proven with pictures that the Sigma 10-20mm is not ideal for IR