Hoya R72 Infrared filter

ripit · 02-07-2012, 08:30 PM

Originally posted by mtngal

jezza - your pictures are awesome! I'm going to have to get out with my trusty K100 and filter some more.

ripit - Auto focus seemed to work pretty well through this filter (I used the kit lens mostly). It sometimes seemed a bit off, but it did better than I did with a manual focus lens and guessing the difference.

The composite picture was fun - I was using a tripod (a necessity with a non-modified camera) and so I took one picture in color then screwed on the filter and took another. When I got home I took both photos, put them both on different layers and then used a layer mask with a gradient to allow the lower layer to show through part of the picture, the gradient making a more gentle transition between the two pictures. The hardest part of that was making sure that I chose to do the transition where the clouds more or less matched.

I seem to recall that being one of the issues with the stronger b&w filter was no chance of auto focusing on a non modified camera. If memory serves, with my canon a70, the r72 could auto focus in very bright sunlight. I just checked the exif on some of my old photos and while a couple were 2 sec exposure, most were more, as much as 15 sec.

Out of curiosity, I tried indoor with the r72, my sony v1 and my ist-ds. Neither could auto focus (kind of surprising on the sony). The ist-ds was wanting a 16 second exposure at f2, where the sony v1 only wanted a 1 sec exposure in night mode I assume at f2.8 (shows how much difference that internal IR cut filter causes). The sony uses an auto focus assist laser array. The laser is not visible but can be seen through the viewfinder, so I'm guessing its IR. Maybe cutting out everything but IR masked the AF assist grid. It will be interesting how they do in daylight?

**mtngal** · 02-08-2012, 01:50 PM

I never tried to focus indoors with the R72 filter, figured there wouldn't be enough reflected IR light to make things interesting. Outside was no problem with either the K7 or the K100 (so would be fine with the DS, don't think the K100's AF was any different). But then, I tried to use a bit smaller aperture to get the dof larger. Or else I was shooting to infinity.

One thing I found was that the filter helped the camera cut through a certain amount of haze, so things that would have been somewhat hazy since they were miles away, were much sharper. I just put the camera into manual focus and the lens at infinity, and got some nice results.

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02-07-2012, 08:30 PM	#16
ripit Veteran Member Join Date: Mar 2010 Location: NewYork Posts: 899	Originally posted by mtngal jezza - your pictures are awesome! I'm going to have to get out with my trusty K100 and filter some more. ripit - Auto focus seemed to work pretty well through this filter (I used the kit lens mostly). It sometimes seemed a bit off, but it did better than I did with a manual focus lens and guessing the difference. The composite picture was fun - I was using a tripod (a necessity with a non-modified camera) and so I took one picture in color then screwed on the filter and took another. When I got home I took both photos, put them both on different layers and then used a layer mask with a gradient to allow the lower layer to show through part of the picture, the gradient making a more gentle transition between the two pictures. The hardest part of that was making sure that I chose to do the transition where the clouds more or less matched. I seem to recall that being one of the issues with the stronger b&w filter was no chance of auto focusing on a non modified camera. If memory serves, with my canon a70, the r72 could auto focus in very bright sunlight. I just checked the exif on some of my old photos and while a couple were 2 sec exposure, most were more, as much as 15 sec. Out of curiosity, I tried indoor with the r72, my sony v1 and my ist-ds. Neither could auto focus (kind of surprising on the sony). The ist-ds was wanting a 16 second exposure at f2, where the sony v1 only wanted a 1 sec exposure in night mode I assume at f2.8 (shows how much difference that internal IR cut filter causes). The sony uses an auto focus assist laser array. The laser is not visible but can be seen through the viewfinder, so I'm guessing its IR. Maybe cutting out everything but IR masked the AF assist grid. It will be interesting how they do in daylight?

02-08-2012, 01:50 PM	#17
mtngal Loyal Site Supporter Join Date: Dec 2006 Location: Wherever I’m Parked Photos: Gallery Posts: 1,003	I never tried to focus indoors with the R72 filter, figured there wouldn't be enough reflected IR light to make things interesting. Outside was no problem with either the K7 or the K100 (so would be fine with the DS, don't think the K100's AF was any different). But then, I tried to use a bit smaller aperture to get the dof larger. Or else I was shooting to infinity. One thing I found was that the filter helped the camera cut through a certain amount of haze, so things that would have been somewhat hazy since they were miles away, were much sharper. I just put the camera into manual focus and the lens at infinity, and got some nice results.