I am using Nikon D850 which is working perfectly fine with my Nikon 50mm f/1.4 lens. Recently I purchased 28-300 lens. I noticed that on mounting this new lens view finder looks quite dark and dim. Same is not the case when other lens is mounted. Is this an issue with lens ? Please advise.


What you see in the viewfinder is what your lens collects. Your 28-300 (a f/3.5-5.6 lens) collects 6 to 16 times less light than your f/1.4 one. This usually not too visible, though. The other possibility is that the lens diaphragm doesn't open up completely, but this would impact exposure.

  • I checked the diaphragm slider on the rear end of the lens, that opens up properly but I am not able to identify whether that is the maximum this lens can open. To add one more thing, live view mode shows better brightness. As good as real view. Jul 22 '19 at 5:28
  • 2
    On most cameras, the electronic viewfinder/live-view screen shows you the picture that will be taken, so this takes the lens aperture in account.
    – xenoid
    Jul 22 '19 at 6:26
  • 1
    The fact that live view is working as expected supports the theory that there is no technical problem — the slower lens is just slower than the fast lens.
    – mattdm
    Jul 22 '19 at 9:14

View finder images (unless in depth preview mode) are produced using fully open aperture, and f/1.4 is a really fast lens. Your 28-300 will have only a fraction of that maximum aperture, probably something like f/4 which would be 3 stops slower and thus admit only an eighth of the light your 50mm prime does.

  • If this is the case then why alone viewfinder? Live view mode shows proper brightness as good as real view. Jul 22 '19 at 5:26
  • @VedantJoshi I think live view electronically brightens things. This is an advantage that mirrorless camera have over SLRs.
    – Eric S
    Jul 22 '19 at 14:03

If you want the viewfinder brightness to reflect actual exposure, your only option is to:

  • Ditch the viewfinder, use the rear LCD in live view mode
  • Purchase a mirrorless camera with an electronic viewfinder to replace the old technology DSLR

No optical viewfinder reflects actual exposure. (Want proof? Set the exposure to a totally ridiculous value so that the image should be completely dark or completely white. You won't see a completely dark or a completely white scene in the viewfinder.)

As others have said, viewfinder shows the view with lens wide open. A 28-300 zoom has relatively small aperture, much smaller than a fast f/1.4 prime.

To answer your question:

Is this an issue with lens ?

Yes, it's an "issue" with the lens, as much as it's an "issue" with the camera. The issue is, that your lens is not fast enough. A constant aperture 24-70/2.8 zoom would be somewhat faster, but then again I wouldn't choose the lens based on viewfinder brightness. I would choose the lens based on image quality, focal length, etc.

  • Previously I had Nikon D3400 APS-C sensor in which I never noticed such difference on switching lens from 18-55 to 55-200 or to 70-300. Does sensor also have to play a role in this ? What i understood so far is what I see through viewfinder is simple reflection of what my lens sees. If that is the case because of aperture, shouldn’t it be same with Nikon D3300 as well ? Jul 22 '19 at 13:05
  • @VedantJoshi It may be the case that some cameras have a dim viewfinder that doesn't show the true difference between lens speeds. Not sure, just wild theory here...
    – juhist
    Jul 22 '19 at 13:08
  • Sorry. Corrected my first comment. Jul 22 '19 at 13:08
  • According to this kenrockwell.com/tech/mirrorless-vs-dslr.htm ...viewfinder cuts at f/2.5 and doesn't show shallower depth of field than f/2.5. It may be the case this varies from camera to camera, and therefore, for your D3400 it could be dimmer and for your D850 it could be brighter.
    – juhist
    Jul 22 '19 at 13:11
  • @VedantJoshi Your 18-55mm (f/3.5-5.6), 55-200mm (f/4-5.6), and 70-300mm (f/4-5.6) lenses were all "slow" compared to your 50mm f/1.4 lens. They're not much different than your 28-300mm f/3.5-5.6 lens. The 50mm f/1.4 lets in about 8 times more light than the zooms do at their widest focal lengths, and 16 times more light than they do at their longest focal lengths.
    – Michael C
    Jul 23 '19 at 21:35

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