Diopter and viewfinder focus differences.

[Chris1701]

Hello all. I'm trying to figure out why all my bird images are always soft, not pin sharp. I'm wondering, if in trying to make the subject look sharp in the viewfinder, compensating for my lack of glasses, would this result in soft images once viewed at 100% on my computer? In other words, am I forcing the lens to focus the image to my unaided eye instead of allowing the lens to do the work and accept the viewfinder image as in focus?

 

[soundbyte]

What make and model camera are we talking about?
Most cameras have a diopter adjustment usually located close to the viewfinder, a must to adjust to your eye/s, depending on which eye you use you may need differing settings for each eye.

 

[DRwyoming]

Hello all. I'm trying to figure out why all my bird images are always soft, not pin sharp. I'm wondering, if in trying to make the subject look sharp in the viewfinder, compensating for my lack of glasses, would this result in soft images once viewed at 100% on my computer? In other words, am I forcing the lens to focus the image to my unaided eye instead of allowing the lens to do the work and accept the viewfinder image as in focus?

Good post above regarding viewfinder diopter adjustment. If you're talking about something like a Nikon or Canon DSLR then there should be a knob to adjust the viewfinder focus and it should be adjusted so all the display information seen in the viewfinder is as crisp and sharp as you can make it.

But also are you manually focusing your photos or are you letting auto focus (AF) do its job? It's hard to accurately manually focus with modern DSLRs through the viewfinder that lacks a precision split focus screen like we had in film cameras. Live view on the camera's rear display can be a much better way to achieve critical manual focus if your camera supports that feature, especially if you zoom in on the live view to focus more precisely. Live View focusing has the advantage the focusing is actually relying on the main image sensor so what the focus system sees is the same as the final image.

If you are trusting normal viewfinder AF but the images are coming back soft you may want to do a focus alignment in the camera assuming your camera supports that feature. This is because the Phase Detect AF sensor in DSLRs is separate from the main imaging sensor so slight changes in the optical path or in the lens alignment can result in images that the AF system thinks are perfectly focused but is actually off a bit from the image recorded on the sensor. AF alignment in supporting DSLRs can generally correct these issues.

And then of course there's always the 800 pound gorilla in the room. What are you using for shutter speed for your bird images? A lot of us (and I'm definitely pointing at myself) who came from film and early generation DSLRs have taken a while to accept that modern DSLRs can run at surprisingly high ISO values without excessive noise. IOW, old habits die hard and a lot of shooters don't run enough shutter speed for birds, especially birds in flight though even perched birds move around a lot more than some folks realize. IOW, is it at all possible that some of your sharpness issues are really subtle or not so subtle motion blur?

 

[Graham Clark]

If you're using a Nikon with a round eye piece (D5, D850, D500 etc), I've found the replacement DK-17M magnifying eye piece helpful.