Lenses in Perspective

With interchangeable lens SLR prices now starting around $400 the popular fixed lens SLR and "quality" pocket digital cameras are becoming all but obsolete. Why pay $800 for a fixed lens digital when you can get more features and flexibility with an interchangeable lens digital SLR at a lower price? If you are shopping for a decent digital camera these days you really need to look at the flexible, full featured digital SLRs that are the fastest growing segment of the digital camera market.

Of course SLR cameras are mainly about the ability to change lenses to suit the task you are performing. Toward that end we have provided impressions of the currently available kit lenses, and information on what lenses will fit each of the digital SLRs discussed in this guide. When you are ready to buy new lenses for your Digital SLR, however, you will also need to know a bit more about how lenses behave on Digital SLR cameras.

Lenses on Digital SLR Cameras

Many readers are familiar with 35mm SLR cameras, but they may not have thought much about SLR lenses since digital started taking over the photography market. Most of the lenses you may already have from a 35mm autofocus camera will work just fine on the new digital SLR cameras. If you currently own autofocus 35mm lenses for Pentax, Minolta, Canon or Nikon, they should work fine on new SLR models from Canon, Sony (Minolta), Pentax, and Nikon. Older manual K-mount lenses will also work on Pentax Digital SLRs and some Nikon manual lenses will work on some Nikon Digital SLR models.

35mm lenses have a different point of view on a digital SLR than you would expect from the lens markings, however. Almost all current Digital SLR cameras use a smaller APS C size sensor that is about 60% of the size of a 35mm image. Therefore the 35mm lens point-of-view appears to be different on a Digital SLR camera. To help you understand how the 35mm lens will behave we are providing a table that translates 35mm lens focal length to the apparent point of view on a digital SLR.

To know what a lens can do on a digital SLR you have to know the lens factor. Nikon, Pentax, Sony, Minolta, Samsung (Sony sensor) and most others use a sensor about 23.6 x 15.8mm with a lens factor of 1.5. This means that if you multiply the stated lens focal length by 1.5 you will get a focal length of how that lens behaves on your Digital SLR. Let's see how that translates.

SLR Lens Factor Conversions
35mm Focal Length 1.5 Lens Factor
Nikon, Pentax,
Sony, Minolta,
Samsung
1.6 Lens Factor
Canon
2.0 Lens Factor
Olympus
10-20mm 15-30mm 16-32mm 20-40mm
14-45mm 21-68 mm 30.15 mm 28-90mm
18-55mm 27-83mm 29-88mm 36-110mm
18-70mm 27-105mm 29-112mm 36-140mm
24 mm 36 mm 38 mm 48mm
28 mm 42 mm 45 mm 56mm
35 mm 53 mm 56mm 70mm
50 mm 75 mm 80 mm 100mm
85 mm 128 mm 136 mm 170 mm
70-210mm 105-315mm 112-336mm 140-420mm
135 mm 203 mm 216 mm 270 mm
75-300mm 113-450mm 120-480mm 150-600mm
500 mm 750 mm 800 mm 1000 mm

Canon uses a slightly smaller CMOS sensor and has a lens factor of 1.6. Olympus introduced a new lens mount specifically for digital photography called 4/3. Olympus and Panasonic interchangeable lens SLRs use this new 4/3 mount, and be forewarned that 35mm Olympus lenses cannot be directly mounted in Olympus Digital SLR cameras.

Entry-Level Digital SLRs Our Picks
Comments Locked

89 Comments

View All Comments

  • finbarqs - Tuesday, December 26, 2006 - link

    I like the XTi's ergonomics, but i guess different strokes for different folks. I do like the fact that Pentax actually feels of high quality, and the biggest problem the XTi is the "cheap" plastic build quality... But i do love their CMOS technology and their noise reduction method!
  • Justin Case - Tuesday, December 26, 2006 - link

    Yes, Canon still has the best sensors (and best telephoto lenses - /me hugs his 70-200 2.8 IS), although Nikon as virtually caught up with the D2X and D200 (and they have the best wide-angle lenses, although Canon's 18-55 2.8 IS EF-S is bloody amazing).

    The XT / XTi is fine if you have small hands, but my big paws will almost cover the lens when I grab one. I hope they release a new model soon, with the 30D / 1D / 5D body and the XTi's improvements.
  • noxipoo - Wednesday, December 27, 2006 - link

    *DROOL* 70-200 2.8 IS, i'm thinking about the 70-200 2.8L, can barely afford that one... anyway, have your tried the XTi with the battery grip? XTi is a good size to me, but bigger wouldn't hurt either.
  • Justin Case - Wednesday, December 27, 2006 - link

    Speaking of battery grip, that's another thing that annoyed me about the XT (and XTi) - they halved the battery's capacity. Sure, now they can say it's lighter (than the original DRebel), but you have to carry twice as many batteries! Duh. I haven't tried it with the grip, but it feels like a hack. I'd rather wait for the 40D (or whatever the successor to the 30D will be called).

    The 70-200 2.8L is great. The non-IS model should be just as good, optically, and a bit smaller and lighter (and cheaper, of course). I bit the bullet and got mine after playing with some similar lenses from other brands, but this one is on a different league. It's actually sharper than some primes on the same range.

    Right now I'm pondering on whether to trade my next vacation for an EF-S 18-55 2.8L IS (I've used one briefly, and it's amazing). It's probably the best autofocus lens in that range from _any_ manufacturer. Of course, that would sort of "lock me" into the 1.6x sensors, but that might not be such a bad thing, if future EF-S lenses are going to be this good.
  • Justin Case - Tuesday, January 2, 2007 - link

    Correction: I mean EF-S 17-55 2.8 IS, of course. The EF-S 18-55 is not f/2.8.
  • noxipoo - Wednesday, December 27, 2006 - link

    has canon said how long they are committed to the EF-S mount? last i heard canon hasn't said a thing.
  • noxipoo - Tuesday, December 26, 2006 - link

    the canon cameras will outsell everyone else by a lot i think, as usual.
  • yyrkoon - Tuesday, December 26, 2006 - link

    I'd like to point out for those who don't know already, and perhaps you "guys" could include it in your articles, or future articles. There are Web sites out there, that sell Cameras at unheard of prices. For instance, when I was pricing the Nikon D80 about 3 months ago, everyone, except on site was selling them at comparable prices. This one web site was selling them MUCH lower than the rest, and there was a good reason. These web sites (some argue are all owned by the same company, just different sites) are rip offs. They mark the camera down, take things like battery packs, warranty, lenses etc out of the kit, and claim, so basically, all you're buying is the camera, and then try to charge you, the customer unheard of prices for these things that are supposed to be sold in the kit. Not only this, these web sites sell cameras, that were originally supposed to be sold in other countries . . .

    Anyhow, if the price is too good, it is, don't fall for the trap. If in doubt, search the web site in question on resellerreviews.com or some such site. Also, I'm not sure why, but google allows these people to advertise with them, and thus, they will likely show at the top of any google search, under featured advertisers . . .

    Luckily, being the cautious person I am, I never got duped, but there are MANY people who have been . . .

  • Wesley Fink - Tuesday, December 26, 2006 - link

    We have seen the same things in online shopping for cameras. It is a common tactic among unscrupulous sellers who always seem to be located in New York City. That does not mean all NY camera sellers are bad, because there are a number of excellent sellers in the city like B&H. If it seems way too good to be true it probably is.

    What you describe is the reason we mentioned in the guide that our prices came from large well-known etailers like Amazon and Newegg. The Amazon price on the entry Pentax K110D kit is currently $452 (or $402 for body only) with a $50 Pentax rebate reducing the price further.

Log in

Don't have an account? Sign up now