D90 Histogram vs Lightroom / ACR

[James Blonde]

When I'm taking photos, I tend to use the back screen and the camera histogram to judge whether I've got the light right. On my IR converted D90, the same applies (and theoretically it's easier as the light reacts differently and it's harder to overexpose as you tend to have a spike in the middle of the histogram, rather than a very spread out one as you would with a colour camera). However something appears to have changed in ACR / Lightroom over the last few months which means what I thought was a perfectly exposed (right in the middle) image in camera comes out horribly over-exposed in ACR. The ACR histogram suggests I still haven't blown the image out, but processing seems to show otherwise, and highlights do appear white. I'm fairly certain this didn't used to be a problem. In fact after import, in the Lightroom image preview, you can watch each image change in turn, from a well exposed and white balanced photo to being slightly pinkish and over-exposed - apparently ignoring the camera settings (I already know ACR has a problem with IR White Balance and I thought I'd catered for that with a custom setting). I understood that this might be down to the camera, histogram and initial ACR preview image working off a preview jpg or something rather than the RAW?

I think I may have to start pre-processing in Nikon Capture, but that seems like such a retrograde step and an unnecessary addition to my workflow.

Any suggestions??

 

[Harlequin565]

(Can't speak for ACR but I know that LR uses ACR profiles so there is much similarity)

Do you set the LR import process to auto-apply the IR profile when you import your shots? That might be the reason for the image changing in Preview mode. I just rebuilt a new computer and re-installed LR and I had to rebuild my IR profile again because the backup one was doing Very Strange Things to my photos. I have no idea why it was happening, but building a new one took about 5 minutes and just worked.

So my first suggestion would be to do another custom IR WB profile and see if that works.

Oh - just had a thought - it's not anything daft like adding a +1 stop of exposure when it's doing the import is it?