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01-10-2009, 05:09 PM   #16
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I know from experience that the K20 focuses as fast, or a bit faster than the 40D with the 40mm limited or 70mm limited in all light levels, ( the 40D with it's 50mm F1.8 ) plus we all know that the pop test was a copy and paste from the K10D, which we know is a bit slower than the K10D.

Where Pentax needs improvement is in AF tracking, mostly with subjects moving towards or away from you, it's fine tracking across the frame. FPS comes next.

01-10-2009, 05:33 PM   #17
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QuoteOriginally posted by Torphoto Quote
I know from experience that the K20 focuses as fast, or a bit faster than the 40D with the 40mm limited or 70mm limited in all light levels, ( the 40D with it's 50mm F1.8 )
Well, the 50/1.8 is a $80-90 plastic budget lens with a rather aged focusing system (non-USM). I've had the 50/1.8 and the 50/1.4 and the 1.4 is smokin' fast comparatively. The 85/1.8 completely blows everything I've ever used away including the pretty fantastic Olympus E3 with 12-60. Price wise the 50/1.4 and 85/1.8 is in the same ballpark as the Limiteds so it's probably a better comparison.

I do have to say the 40/2.8 is wicked fast on a K20D compared to most other lenses I used on it.
01-10-2009, 05:43 PM   #18
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QuoteOriginally posted by UnknownVT Quote
I just posted this but thought it might be relevant here -

Pentax are notorious for being slow in AF in low light levels - there is not that much improvement going from a K100D to even the current top of the line K20D -
here compared to some of the latest dSLRs from Canon, Nikon and Sony (read Minolta)



note the horizontal scale of the K20D is misaligned it should be the same as all the others.
(crops from certified test results from Popular Photogrphy)
Are they heck. Pop Photo admitted that they simply used the K10 results for the K20. My K20D is a lot more precise in low light but Pop Photo blew it.

Incidentally, my K10 was also a lot faster than the K100 as far as I remember and if you look at the chart it is here as well, the K10D EV scale its compressed for some reason making it look worse.
01-10-2009, 06:45 PM   #19
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QuoteOriginally posted by *isteve Quote
Are they heck. Pop Photo admitted that they simply used the K10 results for the K20. My K20D is a lot more precise in low light but Pop Photo blew it.

Incidentally, my K10 was also a lot faster than the K100 as far as I remember and if you look at the chart it is here as well, the K10D EV scale its compressed for some reason making it look worse.
Looks very suspicious to me that they made two such misstakes: missplaced K20D data with K10D and scaled it wrong. Another thing you can notice is that the EV values at which the measurements were made are identical for the canikonys, but completely different values for both the Pentax cameras as if those measurements were made at a separate occasion. Non the less, even with this unclear diagrams (clearly I would have told them to go back and do it all over had they been my students) it is clear that these Pentax cameras was slower, but that was the K10D, right. Then K20D got faster and then...

insert from a post I made in another thread (https://www.pentaxforums.com/forums/everything-else/46182-after-10-years-i-am...tml#post444861):

But...yesterday I've read the first real test of the Pentax K-m in a Swedish magazine (Kamera&Bild, 1/2009). I'm translating:

"The autofocus is a strong side with Pentax K-m even when comparing with the competing cameras from other brands, of which the two most important certainly are Nikon D60 and Canon EOS 1000D. In situations when the Pentax camera just goes on and nail the focus without problems Nikon D60 must use its built in suport light and Canon 1000D has to use a techique with a short seria of flashes to guide the autofocus. The Pentax does not have this sort of focus aid, and seldom need them. On the contrary it is a plus that the photgrapher can shoot in low light conditions without having to draw attention to itself or dazzle its motives."

The author generally rise the autofocus on the K-m to the skies. I assume that this progress will propagate to comming higher models.


01-10-2009, 07:30 PM   #20
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QuoteOriginally posted by Lazaruscomeout Quote
pasipasi, I'm not quite sure I understand what you're saying here.

If I set my K20 to Manual focus and my FA50 to auto aperture and stop it down on the camera, it stays open fully for focusing. This has no impact on my depth of field for the actual shot, which will be at the aperture I have chosen on camera.
There are issues with manual focus on both the K10D and K20D. The stock focus screen shows a depth of field approximately equivalent to f/4 even if the maximum aperture is faster. As a result, it is difficult to do fine focus with a fast lens. That is one reason why I opted to purchase an aftermarket screen with a split image. There are a number of theories about why this may be so, but that is beyond the scope of this thread.

As for the original post...The 40D is faster to lock focus...no question about it. Whether the locked focus is accurate is another question. The Nikon D60 and D80 seem to have about the same focus speed as my K10D. (Not a scientific test...just my impression) I can't say about the D300 since I have never handled that camera.

Steve


Steve
01-10-2009, 08:00 PM   #21
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QuoteOriginally posted by pingflood Quote
I love the K20D but the AF was lacking in performance.
and i love too

IMNSHO I think that the only reason Pentax is loosing new and old customers if some is because the poor AF performance in low light as in tungstenio lights too, is not abot MP nor noise nor WB is AF. How hard is it to fix that pentax? I hope they could hear us
01-10-2009, 08:11 PM   #22
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QuoteOriginally posted by karq Quote
I have a K10D and compared to Nikon D80 maybe and Canon 40D
Pentax lacks in 4 areas - low light AF, predictive AF, P-TTL flash & quality zooms. I have 40D with a few EF zooms and it beats Pentax on all 4 areas by a wide margin.
01-10-2009, 09:11 PM   #23
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QuoteOriginally posted by wlachan Quote
Pentax lacks in 4 areas - low light AF, predictive AF, P-TTL flash & quality zooms. I have 40D with a few EF zooms and it beats Pentax on all 4 areas by a wide margin.

Another loyal member? geez!

01-10-2009, 09:38 PM   #24
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QuoteOriginally posted by Douglas_of_Sweden Quote
The author generally rise the autofocus on the K-m to the skies. I assume that this progress will propagate to comming higher models.[/FONT][/I][/SIZE]
Isn't this just software in the firmware?
Am I wrong in assuming if they corrected it for the K-m/K2000, that it shouldn't be all that hard to roll it over to the K20D? AF subsystems are similar between the two, aren't they? I mean, seriously, the K20D is supposed to be their top of the line.
It would be a bit embarrassing for them if the K-m had a better AF system than their top-line K20D!

Boj's Pen-K site shows the K20D AF as using SAFOX VIII with 11 sensors, the K-m AF as using SAFOX VIII with 5 sensors.
Could it be that utilizing only 5 sensors make it faster?

Tony
01-10-2009, 10:05 PM   #25
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QuoteOriginally posted by vitalsax Quote
Another loyal member? geez!
Until the Pentax people awknowledged the facts and addressed them seriously, their products would be forever behind the competitors. Blind loyality might boost some people's ego, but wouldn't do any good in reality.
01-10-2009, 10:13 PM   #26
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QuoteOriginally posted by Sharkonwheels Quote
Isn't this just software in the firmware?
Am I wrong in assuming if they corrected it for the K-m/K2000, that it shouldn't be all that hard to roll it over to the K20D? AF subsystems are similar between the two, aren't they? I mean, seriously, the K20D is supposed to be their top of the line.
It would be a bit embarrassing for them if the K-m had a better AF system than their top-line K20D!

Boj's Pen-K site shows the K20D AF as using SAFOX VIII with 11 sensors, the K-m AF as using SAFOX VIII with 5 sensors.
Could it be that utilizing only 5 sensors make it faster?

Tony
Perhaps it had to do with the processing power? By keeping the manufacturing cost down, less powerful components have bee chosen? From processing speed, AF motor speed and torque, buffer size to read/write speed, Pentax seem to lack behind the competitors not for the technological reason, but for the cost. Consider Pentax products have been sold at a much lower volume than the competitors, and Pentax consumers are often more price sensitive, they have a difficult time to strike a good balance.
01-10-2009, 10:20 PM   #27
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QuoteOriginally posted by *isteve Quote
Are they heck. Pop Photo admitted that they simply used the K10 results for the K20. My K20D is a lot more precise in low light but Pop Photo blew it.
Yes, I have heard this rumor repeated -
but sorry, I dont' think they did -
I'd be grateful for any corroboration or substantiation of this please?

Both taken from Popular Photography tests

K10D results -


K20D results -


although "similar" - they are materially different enough.

Although PopPhoto does say in their Camera Test: Pentax K20D (March 2008)
" Sticking with the K10D's 11-point wide AF system was a good choice. "
that is NOT the same as they used the K10D AF test results.
01-10-2009, 10:21 PM   #28
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Actually Alan at least in low light I think the reason Pentax and Olympus (IME) fall behind quickly is the lack of AF assist light.. yes I know about using the built in flash to blind the subject in order to get a good focus lock. But this firstly is very annoying for the subjects (or so they told me) and still takes longer the the Nikon AF assist light to lock on.. Actually I was using my AF assist light (from D90) to help Voe (with K10d) to get a focus lock on a xmas lights photo trip, as he simply couldn't lock on without it.. Once I helped him by lighting the subject up he got an almost instant lock..

I don't say this to put down Pentax, but as you say if we are not honest about shortcomings how are they going to improve? same goes for all brands..


On another topic...

Canon, Nikon and Sony all use focus assist lights of one type or another on those POP-photo tested models, did they use the lights? and what distance was the subject? If they didn't then I guess that invalidates my previous comments and the difference is in the AF systems themselves and not just the AF assistance..
01-10-2009, 10:50 PM   #29
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QuoteOriginally posted by joele Quote
Actually Alan at least in low light I think the reason Pentax and Olympus (IME) fall behind quickly is the lack of AF assist light.. yes I know about using the built in flash to blind the subject in order to get a good focus lock. But this firstly is very annoying for the subjects (or so they told me) and still takes longer the the Nikon AF assist light to lock on.. Actually I was using my AF assist light (from D90) to help Voe (with K10d) to get a focus lock on a xmas lights photo trip, as he simply couldn't lock on without it.. Once I helped him by lighting the subject up he got an almost instant lock..

I don't say this to put down Pentax, but as you say if we are not honest about shortcomings how are they going to improve? same goes for all brands..

On another topic...

Canon, Nikon and Sony all use focus assist lights of one type or another on those POP-photo tested models, did they use the lights? and what distance was the subject? If they didn't then I guess that invalidates my previous comments and the difference is in the AF systems themselves and not just the AF assistance..
Based on my own 40D as well as trying different mid-lowend bodies in BestBuy, the issue is not AF assist at all (I have never used it anyway). I think it has to do with the actual AF sensor designs that limit the Pentax low light AF sensitivity. From what I remember, Nikon and Canon AF sensors are more complicated, but I am no expert on engineering to understand them. What I have found when comparing my own Pentax & Canon gears is that while the actual raw speeds (how fast the motor can drive the lens) are pretty much the same, and sometimes Pentax can drive their lenses faster, the Canon still took 1/2 the time to lock AF consistantly in any situations, and become more obvious as the EV drops. One Pentax characteristic is that as the EV drops further, the camera will "think" longer before it starts driving the lens. That means it has something to do with the AF sensor sensitivity, software algorithms, cpu power, or any combinations of these to create such differences.
01-10-2009, 10:51 PM   #30
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QuoteOriginally posted by joele Quote

I don't say this to put down Pentax, but as you say if we are not honest about shortcomings how are they going to improve? same goes for all brands..
..
Yes, you are right.

I have been using manual focus for events these days. So much faster than AF. But Canikon autofocus in dim light is quite superb.


QuoteOriginally posted by joele Quote
On another topic...

Canon, Nikon and Sony all use focus assist lights of one type or another on those POP-photo tested models, did they use the lights? and what distance was the subject? If they didn't then I guess that invalidates my previous comments and the difference is in the AF systems themselves and not just the AF assistance..
True, pending for further clarification
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