Jump to content

Welcome to NikonForums.com
Register now to gain access to all of our features. Once registered and logged in, you will be able to create topics, post replies to existing threads, give reputation to your fellow members, get your own private messenger, post status updates, manage your profile and so much more. If you already have an account, login here - otherwise create an account for free today!
Photo

Getting them "Tack Sharp"


  • Please log in to reply
No replies to this topic

#1
ScottinPollock

ScottinPollock

    Forum Veteran

  • Forum Member
  • PipPipPipPipPipPipPip
  • 598 posts
  • Country Flag
  • LocationWest Slope Northern Sierra Nevada
TL;DR: Use Live View on your DSLRs for tack sharp still lifes.
 
So coming back to my Nikon gear after around six months with the Lumix G9 (IMHO... the fastest, most accurate auto focusing camera for still subjects to date**), my first results were disappointing at best.
 
I was taking some stills of my house and some landscaping work being done and was disappointed in the soft images. These images were focused on the rather neutral gray siding of my home, or on foliage of cedar trees around the property. Something the G9 would have handled in stride, but a D7200 struggled with.
 
After quite a bit of experimentation, I discovered all the soft shots taken with the Nikon could have been sharp had I used Live View's contrast detection auto focus (the same method the G9 uses). Using the viewfinder and the Phase Detect method used with it can be hit or miss, depending on the contrast and lighting presented in the target. This is undoubtedly why I felt I saw so much more "pop" when I first started using the Panasonic mirrorless system. I thought first it must have been the lenses or sensor, but eventually discovered it was simply focus accuracy. I now fully understand why Panasonic wants to continue to develop their DFD CDAF focus technology over Phase Detection, even in the light of it's weaknesses (speed when tracking, hunting in video).
 
So after almost 4 days of testing, I can say that if light is good, and the focus point in the viewfinder is on high contrast areas (like engraving on metal), you can obtain the same level of accuracy as LiveView's contrast detection. But if not, you may get close, but you will have considerably more variation from shot to shot.
 
**Now I'll be the first to admit that PDAF can be faster at acquiring focus in a variety of situations due to it's instant computation of the focal point and focusing the lens on it in one step, especially in video where the back and forth of CDAF (even with Panasonic's DFD tech) is especially visually disconcerting... it is not as accurate. It can seem so with things like BIF and other fast moving objects, but that is a matter of timing, not absolute accuracy. PDAF is guesswork to a large degree, and CDAF is confirmation.
 
One last thing is that there is of course fine focus tuning available in-camera for the off sensor PDAF array with various lenses/focal lengths. I tested a number of lenses and can say that while that may have narrowed the margin I observed between PDAF and CDAF, it did not account for the variability of focus accuracy from shot to shot under PDAF.
 
So if you're doing macro, product, even portrait photography... try firing up that back screen and autofocusing with it. I'd be interested in hearing about your results.