Most lenses for Nikon and Canon APS-C SLRs seem to be much larger than Sony E-mount lenses, despite the sensor size being the same (APS-C). This holds for both primes and zooms, and it holds for the diameter, length and weight.

I understand why the NEX cameras are much smaller than corresponding SLRs. But why are the lenses smaller?

I understand that some SLR lenses are full-frame lenses mounted on an APS-C body, but that explains only some cases (please correct me if I'm wrong). What about the others?

Is it because the Nikon mount is designed for full-frame and imposes an overhead for APS-C lenses? This explanation isn't satisfying, either -- wouldn't that overhead be only in terms of the diameter and not the length? Even the diameter needs to be more only at the point where the lens connects to the camera and not throughout the length of the lens. But SLR lenses are both longer and have a greater diameter than NEX lenses. And in any case, this theory doesn't address Canon lenses. Finally, Sony also shares the E-mount between APS-C and FF, and that doesn't make E-mount lenses bigger, so why would it make Nikon lenses bigger?

Is it just the target market -- people who care about size and weight are more likely to use mirrorless cameras than people who don't care as much, so Canon and Nikon don't focus so much on reducing the size and weight, and even if they did focus on it, their users wouldn't care as much as Sony users?

Is it something special about Sony, or about the E-mount? Are Sony A-mount lenses as bulky and heavy as SLR lenses, or as small and light as E-mount leses?

Or is it something about mirrorless cameras? I fail to see how the camera technology affects the lens, but I wanted to mention it as a possibility.

So, what is it? Why are lenses for Canon and Nikon APS-C SLRs so much bulkier than NEX lenses?

  • 1
    \$\begingroup\$ I'm not that familiar with E mount lenses, but are EF-s lenses really that much bigger? Any EF lens is made for FF and would be expected to be larger, but any EF-s (which is the minority of Canon's lens line up) is designed for APS-c. \$\endgroup\$
    – AJ Henderson
    Jun 5, 2014 at 17:40
  • 4
    \$\begingroup\$ Is 12 question marks in one question a Photo SO record? \$\endgroup\$
    – db9dreamer
    Jun 5, 2014 at 18:33
  • \$\begingroup\$ I once compared the weight of lenses designed for Sony E-mount and "normal" SLR-mount. There is no great difference. A good quality lens is heavier than a cheap lens, as expected, but among similar quality level of lenses for each mount type there was no big difference in weight. \$\endgroup\$ Jun 5, 2014 at 22:37
  • \$\begingroup\$ Not all SLR lenses are "so much larger than Sony E mount lenses". Among the lenses designed to work only with APS-C cameras there are many that are of comparable size and weight to Sony E-mount lenses. \$\endgroup\$
    – Michael C
    Jun 5, 2014 at 23:57
  • 1
    \$\begingroup\$ There are no APS-C sized prime lenses in the Nikon and Canon lens systems, only zooms. Most of those APS-C zooms are smaller/lighter than their full frame counterparts. \$\endgroup\$
    – Michael C
    Jun 5, 2014 at 23:59

1 Answer 1


Actually, they aren't much smaller. Lens size for similar formats is actually pretty comparable, if you look at similarly speced APS-C vs. APS-C designed lenses. Take the examples (on camerasize.com) of 18-55 kit lenses, the 55-210 vs. a 55-250, or crop 35/1.8 lenses.

The size difference is mostly between full frame and crop lenses. But if you look at a full-frame e-mount lens vs. a full-frame EOS lens, say, a 24-70/4, again, the sizes are pretty similar.

The mirrorless lenses tend to get smaller when the sensor (and image circle required of the lens) gets smaller. As in micro four-thirds vs. APS-C.

  • \$\begingroup\$ Thanks, inkista. In the comparison links you've posted, the length of the lenses is indeed mostly the same, but I did find the SLR lenses to be a little wider than the E-mount lenses. \$\endgroup\$ Jun 7, 2014 at 1:54
  • \$\begingroup\$ Think that may have to do with the lens mount diameter ("throat"), too. E-mount has a 46mm diameter; Canon EOS is 54mm. \$\endgroup\$
    – inkista
    Jun 7, 2014 at 19:51
  • \$\begingroup\$ Then why does the EOS lens have to be wider throughout? It can be wide only at its "throat". This is something I asked in my question, as well. \$\endgroup\$ Jun 8, 2014 at 4:22
  • \$\begingroup\$ Probably to keep from impinging on the image circle. \$\endgroup\$
    – inkista
    Jun 9, 2014 at 0:54
  • \$\begingroup\$ Unless you're talking about using an FF lens on an APS-C camera, the image circle of the Canon and Sony APS-C cameras should be the same, which means that the Canon lens shouldn't need to be wider except at the point where it connects to the body ("throat"). \$\endgroup\$ Jun 9, 2014 at 2:23

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.