you telling too different arguments.
the human eye does not see in fps, it doesn't matter if it's 10fps or 1000fps. the human eye see's them all as still images.
what your trying to talk about is about is how your brain processes the information.
yes switching between frame rates produce's a noticeably stuttering effect this is because the illusion of a fluid image is broken. but if the frame rate is maintained, so long as the images are moving fast enough for the brain to trick itself and will adjust to fill in the blanks.
the fact is IF you are sitting there playing at 30FPS and aren't getting a drop in frames the gameplay will appear smoother then if you play a game at 60FPS and are getting a drop of just 10FPS. what matters is the frame rate is a solid frame rate and resolution.
anyone who sits down plays a game at 30FPS takes a break and comes back and plays the same game the same level at 60FPS per second will not tell the difference unless the frame rates are dropping.
the issue is 30 FPS is very near the limit of tricking the human brain which means, Any drop in frame rate is far more noticeable compared to 60FPS.
in any case any lag or stuttering even blur is not caused by the frame rate, it is caused by frame rates shifting. 60FPS is more forgiving, then 30FPS when it comes to frame rate drops. This is one of the reasons movies even without motion blur will always be smoother then video games shot at the same frame rate, because they NEVER drop in frame rate.
it is all down to what is maintained, a notable example of this is crysis 3 where on 30FPS is relatively easy to maintain where as some rigs struggle to keep a solid 60FPS and often drop right down to 40FPS making the game unplayable. compared to running at 30FPS and many gamers saying "what the ****"
it all comes down to maintaining a solid frame rate, if 30FPS can for the most part be maintained then there is no noticeable difference, suggesting someone compare 30fps to 60fps side by side is useless because your defeating the purpose of frames per second in the first place which is to trick your brain into thinking your looking at a fluid image.
There is a very clear and demonstrable difference in visual fluidity between a constant 30fps and 60fps. While you make a valid point about severe dips in frame rates causing issues in perceived smoothness, certain situations of lag or stuttering can definitely be attributed to lower frame rates, even if at solid consistent rates.
Video games are being artificially rendered and are not simply a series of still images displayed in a rapid succession. Thus the effect of motion blur is something of little to no benefit in video games. Add in the interactivity of the medium, the slower the game is rendered on screen, the more noticeable the lag can be between user input and the actual displayed action. This is why faster paced games like first person shooters benefit so much from higher consistent frame rates.
If you think seeing side by side comparisons between 30 and 60fps are useless, then here is a link to one where you control which frame rate is being rendered on screen. The difference is noticeable.
http://www.30vs60fps.com/
For a more related demonstration between the two, here is a link to the DAI - Gameplay Features: Combat video with 30 and 60 fps version available.
http://www.gamersyde...t-32686_en.html
What is considered a playable consistent frame rate will vary from person to person and will also largely depend on what they're used to. But the fact of the matter is a game rendered at a consistent 60fps will be a far smoother playing experience than not.