the K3 is perfectly tiimed to hit C and N where they hurt

Started Nov 4, 2013 | Discussions thread
Ian Stuart Forsyth
Ian Stuart Forsyth Veteran Member • Posts: 3,409
Re: the K3 is perfectly tiimed to hit C and N where they hurt

paulkienitz wrote:

paulkienitz wrote:

tcom wrote:

Well, the sad part is that should a photojournalist take the K3 for events photography and use it with the lens with the equivalent 70-200 range, the DA*50-135/2.8, will notice that the fast action packed camera is useless for what he intends to do since Pentax features almost the slowest AF on this lens in the whole lens offering (with the exception of the DA*55 which is even slower). When asking Pentax, he will receive the same reply as I have gotten, we are not the target audience of Pentax... That's why I added nikon a few years ago. Still today, Pentax seems to make no effort in redesigning a 50-135 with an AF fast enough for concerts or sport events... The fastest camera is useless when the brand can only offer slow focusing lenses.

Are the lenses slow to focus, or is it the handicap of IBIS on a DSLR that makes it harder for the sensors to lock focus on an unstable / unstabilized image? C and N use optical stabilization in their DSLR's and I think it's for more reason than to charge extra for stabilized lenses.

The idea thwt IBIS inhibits focus is completely baseless. The two have nothing to do with each other.

You are correct, but lens base stabilization in low light allow the AF sensor to stay on the target with less movement during the time its takes to AF, giving assistance to AF in low light and many times a fast and more accurate lock. This is really amplified when using larger telephoto lenses when none stabilized have fast little jittering movement when handheld and under lower light will impede with fast AF lock but when they are stabilized there is less movement for the af to work more efficiently.

In theory that may be a problem... just as in theory it can be argued that optical stabilization might be superior to sensor stabilization on very long lenses. But we don't have to debate theory: Pentax users have the oppirtunity to actually compare both kinds of stabilization on the same oens, when using something like the Sigma 150-500 OS. And so far, all I've heard is that the two approaches show no significant difference in effectiveness. Of course, how it will work with the K-3 autofocus in particular hasn't been reported yet.

From my experience have lens base stabilization has the edge over body starting at 200mm, that comparison is made with VRII base lens compared to a K5 This can be seen in video and still photos and about the only way I can illustrate this is shooting video with both one with a 300mm on k5 and the other with a D800 shot in dx with a 300mm lens. This video reflects my findings in the field using lenses all the way up to 600mm.


This photo was taken in EV -4.6 light using a tripod with the D800 200-400 and 1.7 conv wide open at 6.7, I was unable to get AF lock until VR was engaged and repeated this lock several times while using vr. I have had several occasions where I needed VR with longer glass in low light and on targets with low contrast to help obtain faster AF locks. Also the use of VR with tc can also give faster AF locks under normal lighting conditions so from my personal experiences I can say yes stabilization of the projected image onto the af sensor is an advantage over in body stabilization. This photo was not for artistic merits and was only taken to identify the night visitor we had tonight. This is also ironic that the D800 that is only rated to ev -2 for low light af and here it was able to AF lock in ev -4.6 with the additional hindrance of a 1.7 tc.

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