Nervous nellie...go with Pentax K-1 or move to Sony FF?

Hello Jhaakas

Jhaakas wrote:

KPM2 wrote:

For that I use this example:

It's a f3.5 at 103mm low light picture, taken with a APS-C camera, the K5.

When I use now my K1 for that, my lens could still capture the same picture, now @ 154.5mm,

On K1, you can still keep fl at 103 mm, aperture at 3.5 and crop. That will be the similar

because it's a 80-200mm and FF lens. For to reach the same DOF like in the picture above (and it's DOF is already very thin) I had to close the aperture about one stop more, when I would use the K1.

Look at this the other way. If you take a photo with K1 @ f3.5, you will need an aperture of maybe f2.4 on apsc and such a lens would be very expensive!

So a FF will give u what you want in crop mode, but not the other way.

You are right, but I try to write about an other situation. I use APS-C cameras (K5 and KP) and a FF camera (K1). When I look at the Sony, it's clear, it's fantastic to have a AF system which can focus precise with a fast lens full open. When you count now in, that you have via FF even a thinner DOF, a not so precise AF system would let you see AF miss focus results in a picture. OK, so far so good. On the other hand, using a FF camera do not have the goal to get always a thin DOF. Therefore I used this example. For to get the same DOF as with a APS-C camera, you have to stop down your lens about one stop more. Therefore, using a lens not at full open is not a so seldom situation, even for such low light situation like in my example. Sony cameras do use a stop down mode for the lens when you use AF-C. That is simply not ideal for the AF system in low light situations. Meanwhile I use a fast f2.8 lens, for that the AF system have it easier in low light situations like in the example, but take the picture for to have a bigger DOF not at full open, a fast f2.8 Sony lens can do not help the AF system, because it get stopped down than, and the AF must work with a lens, as if it is a slow consumer lens. For my camera it's like I would use my DA 55-300mm f4-5.8 instead of the FA*80-200mm f2.8. I really hope Sony change that.

best regards KPM2