[stevebrot]

What does price have to do with anything?

Value and performance are not always linked. Some of the most expensive cameras you can buy don't even offer AF.


Steve

[audiobomber]

Someone made a point that Nikon users would ignore any results not using a Nikon lens. I believe that is true. I'd like to see the K-3 with DA*300 vs. Nikon and/or Canon top APS-C bodies, and their native 300mm f/4. That compares systems and bodies, with similar spec and price levels.

We took two top-shelf and comparable lenses from each manufacturer, which is a very realistic test IMO.

A FF collects twice as much light as APS-C. F/2.8 collects twice as much light as f/4. The D610 had four times as much light to work with.

the D610 has an old AF system, so the D7100 would do better if anything.

Maybe, but where's the proof?

[bxf]

What does price have to do with anything?Steve

If you want the best performance for a limited budget, it has everything to do with it.

Value and performance are not always linked. Some of the most expensive cameras you can buy don't even offer AF.
Steve

This statement implies that AF is the only feature that determines price or value. In other words, you're saying that if a camera has no AF, it has no business being expensive.

Also, I would add to your comment and say that value and price are not always linked, contrary to the popular myth that "You get what you pay for". I've had too many exceptions (in both directions) to believe in this philosophy.

[Adam]

A FF collects twice as much light as APS-C. F/2.8 collects twice as much light as f/4. The D610 had four times as much light to work with.

Two times, but all this is saying that Pentax needs to come out with a longer F2.8 lens

Adam
PentaxForums.com Webmaster (Site Usage Guide | Site Help | My Photography)



PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

[Nesster]

My guess is straight up the K-3 will outperform the Nikon 7100 in raw continuous focus testing. That does not entitle one to say Pentax AF is better than Nikon. I will hazard a guess that the Pentax K-3 is the best AF cropped camera currently made. Reading the review one would never come close to guessing that might be possible. I feel the test was a case of self fore-filling prophecy designed to prove the testers initial assessment.

And you base you guess on what?

Historically, Pentax has lagged Canikon in AF, and there's no shame in admitting that. And to me if Pentax got close to a more-expensive Nikon is a good thing, and indeed is close to revolutionary... In practice, of course depending on what you shoot, a valid comparison is, say, how accurately does the camera lock onto a model's eye, using similar lenses. Or, the follow the moving object test Adam ran.

We need not hush up where Pentax may come short of the competition just because Pentax comes out ahead in so many other areas.

[David&karen]

Having owned the Nikon 70-200 f2.8 VRII lens on a D3X I can say it is one of the fastest focusing lenses Nikon has, much faster than even the newest Sigma 70-200 OS HSM lens. I compared that Nikon lens to the Pentax 60-250 that I rented from Lens rentals last year on a Pentax K5IIs and it was nearly double the speed, it's that fast. Even if this test was re-done with a Sigma 70-200 OS on the K3 the Pentax is still at a disadvantage due to the speed of the lens motor, not the camera. I just put the Tamron 70-200 f2.8 on my K5II and it is still about 40% slower than the video on your tube of the Nikon 70-200 VR2(the 17 second one if you look) going through it's entire focus range....The Tamron focuses closer though so that is a factor. And the Nikkor can limit it's focus down to 5m which essentially makes it instant focus, no lag. I feel the only fair thing here is a D7100 and K3 both with the Sigma 70-200 f2.8 HSM OS lens. That way just about everything is on an even keel and it comes down to how the camera handles the AF. The crop factor is the same for both it eliminates as many differences as possible. Until then I am taking that section with a very large grain of salt, with my apologies to Adam who I have confidence did his best in a very short time frame. If you want to see the Nikkor vs the current Sigma lens focus speed, Matt Granger has a video comparing the 2 plus the Tamron 70-200 f2.8 model that we have in Pentax. A note on that video: The Nikon model of the Tamron has a built in motor OR is screw driven depending on vintage. They are both loud when they focus so I did not consider that model when I was looking at the video. 2. Matt Granger at first says the Nikon is the same speed focusing as the OS Sigma, then corrects himself as it's apparent that the Sigma is slower. You can see the lens' focusing scales as he does this, so judge for yourself. YMMV as usual,

David

[audiobomber]

Two times

More than four times. F/2.8 vs. f/4 is twice as fast, and then there's the FF conversion.
F/4 on APS-C = f/6 on APS-C.
So your AF test was f/2.8 vs. f/6.

[Adam]

More than four times. The aperture is twice as fast, and there's the FF conversion.
F/4 on APS-C = f/6 on APS-C.
So your AF test was f/2.8 vs. f/6.

F4 on APS-C = F4 on full frame = F4 on the Q = on any format

[Canada_Rockies]

F4 on APS-C = F4 on full frame = F4 on the Q = on any format

I think, Adam, the poster was referring to the size of the individual pixels, each of which captures more light on FF, given the same Mp rating. 24 Mp on 24x36 takes in more light per pixel than 24 Mp on 16x24. I have no idea, myself, what possible effect this could have on AF.

[audiobomber]

F4 on APS-C = F4 on full frame = F4 on the Q = on any format

Try mounting a Q 15-45mm f2.8 on a FF and see how much light you get.

[Adam]

I think, Adam, the poster was referring to the size of the individual pixels, each of which captures more light on FF, given the same Mp rating. 24 Mp on 24x36 takes in more light per pixel than 24 Mp on 16x24. I have no idea, myself, what possible effect this could have on AF.

It's completely irrelevant for the AF. The sensor and its pixels aren't part of the AF system unless you're using live view.

Try mounting a Q 15-45mm f2.8 on a FF and see how much light you get.

The exposure will be the same, but it won't cover much of the frame.

[audiobomber]

I think, Adam, the poster was referring to the size of the individual pixels, each of which captures more light on FF, given the same Mp rating. 24 Mp on 24x36 takes in more light per pixel than 24 Mp on 16x24. I have no idea, myself, what possible effect this could have on AF.

No, nothing to do with that.

Aperture value is the focal length divided by the diameter of the aperture opening, in mm.
100mm lens, 50mm diameter opening = f2 lens.
Except when you mount that lens on a 1.5X crop camera, the FOV changes to a longer equivalent focal length. Now you have 150/50mm = f/3 equivalent.

[Adam]

Aperture value is the focal length divided by the diameter of the aperture opening, in mm.

Focal length does not change based on the format being used, hence the aperture value does not change either. If you were to put the 70-200mm F4 on the D610, its AF sensor would get just as much light as the K-3 with the 60-250mm F4.

[Canada_Rockies]

Sorry, Dan, but the f/stop is the f/stop. All the APS-C difference is, is that it doesn't see the whole 24x36 frame. The brightness level in the area that sees the lens is exactly the same. Lumens per square millitmetre doesn't change at all.

[monochrome]

My few cents - and maybe nobody cares. (And I won't have a K3 until after February 10th)

• We're all captives of our past experience with Pentax, in that this AF improvement would be the last. best effort Pentax would make for many years. Consequently we view the K3 vs. (competitor) argument as static and binary. We want to compare and contrast, pick a winner and close the book, as follows:
  • This AF is either revolutionary or evolutionary
  • This AF is either better than or not better than (competitor)

I contend head-up competition shouldn't be the point of reviewing the K3. I contend this AF is much better than what we had in prior Pentax cameras. Whether objectively (as tested for) or subjectively (as reported by users) or personally discovered (when I get mine), this camera can perform focus functions differently than and better than any camera branded Pentax has ever done before. And I contend this won't be the last AF improvement we see from Ricoh.

I further contend the big change Ricoh brings to the table will be (later seen to be) constant, iterative change, as opposed to infrequent, disruptive change.

• This AF isn't static, it is dynamic. The next generation of Pentax cameras will have better AF - perhaps faster, perhaps more precise, perhaps eye-recognition, perhaps tracking.
• This AF (may well) pair with new lens designs to further improve final performance, which we cannot know until the entire range of lenses is refreshed with an as-yet-unrevealed technology - and brand new designs are released.

The same principle applies to many other systems

• flash technology - the new ones are better, but not yet as good as Nikon
• Shutter - the new one is better, but not yet up to 1/250 sync capability (see flash)
• WB - we haven't really seen tests yet, but the new multi area WB is probably better, but not yet revolutionary
• Metering - same as WB
• Buffer - faster but perhaps not world-class
• Processor - faster - possibly best-in-breed
• Sensor and conversion algorithms - jury is out, but it will get better
• Ongoing Firmware improvements - iterative improvement, and the sky's the limit

And so on.

The K3 is a very very good first effort for Ricoh (total Ricoh design). It probably isn't head and shoulders above anything, and maybe a bit behind competitors' best efforts in some areas. It isn't the last step and needn't be reviewed as a once-a-generation, standalone device. It is a step in a constant progression of change and improvement - that's the good and big news.

We'll have to wait and see whether Ricoh releases similarly evolutionary or completely revolutionary lens designs, some complementing accessories and makes the beginnings of some credible distribution structure investments.

At the end of the day, though, the K3 is an excellent chioce, and probably good enough to satisfy the needs of any but the most demanding users. That should be the conclusion of EVERY review.