[paperbag846]

Go Nikon if you want the best AF.

[Douglas_of_Sweden]

Go Nikon if you want the best AF.

Really?!

Some hard numbers. The journal FOTO, the oldest photographic magazine in Sweden, tested the K-r in their 2011 January issue. Here is the autofocus speed compared to what they consider similar Canikon models (with similar lenses, all 18-55 kit zooms):

Penta K-r at 18, 35 and 55mm: 0.30s, 0.35s, 0.39s (shutter-delay 0.08s)
Canon 500D at 18, 35 and 55mm: 0.28s, 0.31s, 0.31s (shutter-delay 0.13s)
Nikon D3100 at 18, 35 and 55mm: 0.31s, 0.45s, 0.47s (shutter-delay 0.13s)

The Pentax and the Canon is so close that taking the shutter-delay into account, the K-r is the faster camera at 18 and 35mm. Nikon is clearly behind both Canon and Pentax. This is a journal I trust to be unbiased and to take tests seriously (even to the degree that I'd think this is average values, not single measurements). Pentax K-5 will be tested in the next issue, against comparable models.

[orly_andico]

I think at the entry level (D3100, 500D, K-r) the performance of the different brands is comparable or statistically similar. The FOTO test shows that: the entry level Canon lens has a micro-motor drive, ditto for Nikon. These aren't Silent Wave or Ultrasonic lenses.

It's pertinent to note that the shutter release lag of the Canon 1D Mk IV is 40 milliseconds. That's 0.04s or about 1/3rd of the quoted figures for the entry bodies (at 10X the price).

It's like comparing Honda and Audi. If you compare a Honda Accord and an A4, you might actually believe Honda makes the faster car. But Audi also makes the R8......

[Digitalis]

Go Nikon if you want the best AF.

I wouldn't say Nikon has the best AF but it is heavily customisable, and has plenty of AF points. Which is something pentax should take note of. Canon is pretty snappy too, however I was using a K5 and the sigma 100-300mm f/4 at a soccer game and the sigma is extremely fast focusing, and I really didn't notice much of a difference in AF between my pentax and my Nikon D3s with the AF-S 400mm f/2.8G ED VR sure the nikon locked on quicker when using AF tracking, but the rate of keepers from either camera was pretty much equal.

[Abstract]

I found a nice article on auto-focus. Digital Photography I tend to side with it. Point being if you are not doing sports or quick sudden movement photography, manual focus is better most of the time. I can catch fast moving stuff with manual focus myself but I can see why for some it may pose a problem. I can't say much about Auto-focus on Pentax, I can in a couple days when my K20D arrives with the 18-55mm WR lens I ordered. I used Nikon before this and mostly Manual focused(99 percent of the time).

It comes down to Manual being more accurate since its your eye telling it when to shoot and not a computer.

[orly_andico]

I used to believe this.. and have a split-image viewfinder in my K20D.

But there are lots of subjects (not just sports) where manual focus is very challenging. For example, portraits with fast lenses like the 50/1.4 or 85/1.8 wide-open. Your subject moves just a bit, and focus is thrown off, no more sharp image due to shallow DOF.

Chasing kids around at close range is another use case where fast AF is useful.

[Abstract]

Oh yeah, its useful in certain situations, that 1% is me being lazy at family things or out with friends...maybe its more like 5% haha...I do prefer manual though.

[Jodokast96]

It's not even about the subjects a lot of the time. A lot of us just can't see well enough to manual focus. Even with my glasses it's more than a challenge.

[Arpe]

Some hard numbers...

Penta K-r at 18, 35 and 55mm: 0.30s, 0.35s, 0.39s (shutter-delay 0.08s)
Canon 500D at 18, 35 and 55mm: 0.28s, 0.31s, 0.31s (shutter-delay 0.13s)
Nikon D3100 at 18, 35 and 55mm: 0.31s, 0.45s, 0.47s (shutter-delay 0.13s)

Of course it depends upon lenses used too.

I believe the Pentax AF is fast, maybe as fast as the others (no experience for me). But I understand the TRACKING focus to be lacking in Pentax, so keeping up with the changes required typically when shooting sport. That's the crux of the matter FOR ME.

[kari]

I think the tracking AF capability is heavily dependent on the lens. With the 18-55 I don't have any problem tracking birds flying towards me with the K-x, but the 55-300 is too slow to keep up.

[Rondec]

I used to believe this.. and have a split-image viewfinder in my K20D.

But there are lots of subjects (not just sports) where manual focus is very challenging. For example, portraits with fast lenses like the 50/1.4 or 85/1.8 wide-open. Your subject moves just a bit, and focus is thrown off, no more sharp image due to shallow DOF.

Chasing kids around at close range is another use case where fast AF is useful.

Kid photography is tough whatever you use, because they are so random in their movements. "Predictive" auto focus doesn't work particularly well when there is no predictability with regard to movements. I doubt even a D3x could track my son when he is on the move...

[kryss]

I used to believe this.. and have a split-image viewfinder in my K20D.

But there are lots of subjects (not just sports) where manual focus is very challenging. For example, portraits with fast lenses like the 50/1.4 or 85/1.8 wide-open. Your subject moves just a bit, and focus is thrown off, no more sharp image due to shallow DOF.

Chasing kids around at close range is another use case where fast AF is useful.

I can't but think how we older photographers managed to take portraits and moving objects in perfect focus using our manual focusing film cameras and lenses,and also ending up with more keepers.I even believe National Geographic still have at least one photographer who still shoots film only and shoots appx.3-5 thousand rolls per assignment.

[MrPetkus]

I'm fairly deft at manual focus fan and use the KatzEye and magnifying eyepiece. However, in low-light/low-contrast scenes (especially when using a wide aperture) I have difficulty resolving the image. In those conditions I need AF if I expect to receive any satisfaction upon uploading the pics into Lightroom.

I found a nice article on auto-focus. Digital Photography I tend to side with it. Point being if you are not doing sports or quick sudden movement photography, manual focus is better most of the time. I can catch fast moving stuff with manual focus myself but I can see why for some it may pose a problem. I can't say much about Auto-focus on Pentax, I can in a couple days when my K20D arrives with the 18-55mm WR lens I ordered. I used Nikon before this and mostly Manual focused(99 percent of the time).

It comes down to Manual being more accurate since its your eye telling it when to shoot and not a computer.

[RAMOS79]

Would it be sacrilege to mention video as a means of capturing rapid toddlers, with stills for the quieter moments?

Makes sense to me. Video for the high energy moments and stills for when the young ones wind down.

[jsherman999]

I can't but think how we older photographers managed to take portraits and moving objects in perfect focus using our manual focusing film cameras and lenses,and also ending up with more keepers.I even believe National Geographic still have at least one photographer who still shoots film only and shoots appx.3-5 thousand rolls per assignment.

This is a common refrain, and if you look through the archives of professional and art photographers from those days, you see a lot of brilliant, sharp images that were taken with MF lenses.

However - look through a lot of old photographs taken by enthusiasts (like most of us,) and you'll see a lot of soft shots due to focus errors. I was just looking through an album of selected shots published by a local paper in the 1970's and 80's, shots taken by some staff photogs and many submitted by SLR-owning readers, and there was a lot of softness, a lot of Bf/FF. I think these shots were acceptable for the paper because they were close to the norm in those days - exact focus was not expected in everyday photography like it is today.

I see the same thing in family photo albums. The shots taken by my grandpa and uncles in 1974 with their spotmatics just are inconsistently in focus. The lenses themselves were great, they were shooting with Takumar primes, etc.

IMO, the 'we somehow got by in the MF days' argument is literally accurate - but 'getting by' at the enthusiast level back then would leave something to be desired today - IMO, from what I've seen.



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