Photo Gear Shuffle

March 11, 2007

There’s been some significant rearrangement in my camera gear. Gone are the Nikkor 20-35mm f/2.8 wide angle zoom lens, and the Nikon SB-28 speedlight flash. In their places I have put the Sigma 18-50mm f/2.8 Macro wide-angle zoom lens and the Sigma EF-500 flash.

I also realized that I should need a good bag for all this stuff, so on the recommendation of a knowledgeable friend I ordered this Domke Super Compact.

New gear arrives tomorrow. Should be fun. Especially the Sigma 18-50mm lens. It’s very similar to the Nikkor it’s replacing in that they’re both pretty wide zoom lenses with a bright f/2.8 all the way through the zoom range. There is a small difference in that the Sigma is 18-50mm, whereas the Nikkor was 20-35. No big deal. Looks like I get a little more telephoto with the sigma, because it goes all the way out to 50 instead of just 35. The difference on the wide end is negligible.

But this is deceiving. [UPDATE: the paragraph and the next draw the wrong conclusion. For a clarification see this subsequent entry.] The Nikkor was made for 35mm film cameras (here the number doesn’t mean the focal length of the lens, it means the diagonal dimensions of the film that the image is projected onto inside the camera). But since most digital cameras have a sensor that is smaller than 35mm, they only capture the center of the projected image. This makes these lenses more telephoto when put on a digital camera than the numbers on the lens would indicate. In fact, to know what the effective focal length of the lens will be when you put it on your digital, one usually multiplies it by 1.5. In other words, the Nikkor with it’s focal range of 20-35mm is effectively 30-52.5mm on my camera.

Not so with the Sigma. It was designed for digital cameras, so the focal length printed on the side is what i’ll actually get: 18-50mm really means 18-50mm. So you see what I’m effectively gaining with the Sigma is quite a few more millimeters of wide, but not much change at the telephoto end. One nice upside to this is that the lens can be smaller and lighter while giving me a similar result. One downside to this is that the lens will not be usable on 35mm film cameras pr digitals with 35mm sensors (though there are few of these). Thus instead of the Sigma giving me a few more millimeters of telephoto based on the printed numbers, it’s actually giving me a few more millimeters of wide after you apply the 1.5x multiplier to the Nikkor.

So here’s where things stand lens-wise:

18 – 50mm from the new Sigma f/2.8

75mm (effective) from my super bright 50mm Nikkor f/1.8

42 – 120mm (effective) Nikkor AF G 28-80mm f/3.3-f/5.6 zoom

That’s not bad: I get from 18mm wide-angle all the way to 120mm telephoto, with some really bright f options all the way through 75mm. What I wish for now is bright telephoto out to 200mm.


No comments yet

  1. I was looking at the Sigma 18-50mm and the Tamron 17-50 f2.8. According to the experts at Mike Crivello Camera, you still need to apply the digital imaging sensor multiplier even for lenses designed for digital cameras including the Sigma DC lenses (18-50) and the Tamron Di II. For my Canon E30D, the Sigma is effectively a 29-80mm. I also thought these lenses were designed to the actual focal length. All the new 18mm lenses at the low end of the zoom range are replacing the 28mm for film cameras. I was set to buy one of the two lenses mentioned above, but I am now rethinking my lense combinations. Anything in a Canon lense with f2.8 starts at $900 and with the right focal lengths is around $1400 – $1700. All the reviews indicate the have marginally better optics, faster auto focusing, and built for more rugged, professional use. Some have image stabilization. Really nice for the pros, but out of range for most amatuers. They really seem to be handing the comsumer market to after market manufacturers like Tamron, Sigma, Tokina and Quantaray.

  2. Well, I can say one thing for absolute certain: the Sigma’s 18mm is way, way wider than the Nikon’s 20mm! I don’t know what kind of crack the guy is on at Crivello’s, but it’s very clear that the 1.5x multiplier doesn’t apply to the Sigma. When it says 18, it means 18, whereas the Nikon said 20 but really meant 30.

  3. I checked with Art’s Camerea and Wolf Camera as well as some internet investigation – you still need to apply the multiplier to “digital” lenses. The Nikon multiplier is 1.5, for most middle range EOS Canons and lower is 1.6. The Canon EOS 5D has a full size (35mm) sensor so the mulitplier is 1.o and accepts all film camera focal lengths as specified. Apparently, all focal lengths are referenced to a full frame 35mm standard, whether designed for digital cameras or not. Even though the Sigma 18-50mm appears wider, the multiplier still applies. I currently have a Tamron 28-200 f3.5/5 from my film camera on an EOS 30D and would be happy to just to get back to the true 28mm view. As mentioned, I was ready to buy the Tamron 17-50mm f2.8 Di II digital camera lens until I found out that the conversion factor still applies. I’m checking into wide zooms 11-35mm f2.8 or lower and cost. I still may buy the Tamron 17-50 or the Sigma 18-50 (they are both highly rated lenses) if I can’t find a reasonably priced lens with a wider low end in f2.8. Check


    for info on lens multipliers for digital camera lenses.

  4. Sorry for the reference to Wolf Camera, they are now Ritz Camera. I still think of them as Wolf camera. I would be interested in how the Sigma flash is working, since the equivalent Canon flash is three times more in cost for similar features.

  5. Now I’m confused myself! I am trying to get a definitive answer for what the deal is on the focal lengths by consulting the guy who’s been shooting as a pro for over 30 years.

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