Jeremy's almost but not quite entirely moribund blog

Saturday, September 23, 2006

Looks like I'll get the 400D/Rebel XTi after all has their review of the Nikon D80 up. I was looking forward to this review not because I plan to buy that camera, but because I figured they'd compare it with the Canon Rebel XTi, which I was considering. I wasn't disappointed.

The information I was most interested in finding is the actual sensitivity of the XTi at various ISO settings. In the past, Canon's DSLRs have been 1/3-stop more sensitive than indicated. There was some concern on the dpreview forums that the XTi was actually 1/3-stop less sensitive than indicated, which would have been a deal-breaker for me since low-light photography and astrophotography are high priorities.

Anyhow, the professionals have spoken. The 400D/XTi is not less sensitive than the 350D/XT. The table at the top of the noise comparison page shows the XTi still maintains the +1/3 EV sensitivity margin from previous Canon DSLRs. The darker images people have noticed compared to the 350D/XT must be a difference in tone curve, not sensor sensitivity. Since the older camera was known for blowing out highlights, many view the change as a good thing.

The noise comparison on that page looks quite favorable for Canon; even though Nikon achieves numerically lower noise values at ISO 800-1600, they achieve it by blurring away detail. The XTi certainly has the edge. The ISO 100 studio comparison also shows a slight advantage for the XTi in terms of image crispness as well.

In fairness to Nikon, the D80 looks like a very solid camera overall; it certainly has advantages over the XTi (the major one being the D80's larger, brighter viewfinder), and any image quality deficiencies compared to the XTi are extremely minor and would only be noticeable to pixel peepers such as myself. :) The main drawback to the D80, for me anyway, is that it costs $200 more than the XTi (which already strains my budget for accessories).

EDIT: Turns out Phil was initially wrong--the XTi is 1/3 stop less sensitive than the XT after all. In other words, ISO 1600 is ISO 1600, not ISO 2000. Not a huge difference, but a bit of a let-down, and a lesson on why not to be an early adpoter. (Says the guy who bought a 2007 Toyota Sienna on January 1, 2007.)


  • Hi Jeremy,
    I have just started looking around for a Mount (and motor drive) to attach my camera. Did you buy the XTi? And if so, have you used it on your EQ-1 mount?

    I'm thinking of getting the EQ-1 mount and use it with my Nikon D90 for time elapsed pictures (with the optional tracking drive).

    Gary. gary at

    By Blogger Gary, at 8:37 AM  

  • I haven't used my XTi on my EQ-1; I returned the EQ-1M drive when I found its steppers didn't pulse smoothly enough for long focal length photo work (you could see the target zigzag back and forth). If you're just looking for wide-sky photos (< 50mm or so), the EQ-1 would probably be serviceable.

    By Blogger Jeremy, at 1:31 PM  

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