Focusing Speed

[holidaydom]

People often comment that OLYMPUS cameras focus slowly, but what actually contributes most to the speed at which the camera is able to lock focus?

Image composition aside...

1) Camera Body?
- No. of focus sensors; no. of cross-type sensors
- Processing speed and focus aglorithums
- Sensivity of the focus sensors

2) Lens?
- How significant is the difference between a "normal" motor and SWD?

3) Max aperature?
- This one is for sure, a bigger max aperature = a brighter image and so the focus sensors are ebtter able to evaluate and determine focus.


Bottom line - which one has the bigger effect on overall focusing speed: the Lens motor or camera body?

.

[marky]

I'm not too sure but correct me if i'm wrong.. i think its the number of focus sensor in the camera body that makes focusing slow.. but i've gotten used to it but in low light still ait pek chek.. haha.

[holidaydom]

Originally Posted by marky I'm not too sure but correct me if i'm wrong.. i think its the number of focus sensor in the camera body that makes focusing slow.. but i've gotten used to it but in low light still ait pek chek.. haha.

My thinking is similar but I don't think that it's the number of focus-sensors but more of the quality of the sensors in terms of their light-sensivity (low light) and also the processing aglorithums in the camera.

I'm thinking that the camera body is the bottleneck and that the lens motor isn't really a big factor compared to the body.

[bousozoku]

The three focusing sensors and the poor low light capabilities (up until the E-410 and E-510) have pretty much crippled the auto focusing system but I don't use it anyway.

The motors may be slower than ultrasonic motors but I believe that it's mainly that the sensors are trying to find enough light in many cases.

[schon]

i think it's algorithm and processing speed.

[OlyFlyer]

Definitely the focusing motor speed is the most important factor. F-number of the lens has nothing to do with it. The ED 50mm is f2.0 and thus it should be the fastest to focus. The 14-54 is f3.5 at 54mm but it definitely focuses much faster. Of course, if you don't care about composition and can accept to focus anywhere, it would be better if we had a few hundred focusing points of cross type, but according to me, the center is fast enough with a good (speedy) lens motor.

Algorithm and processing speed has nothing to do with it, since it is anyway far too fast for our brains.

I have no idea about the difference between a "normal" motor and SWD, I have four Oly lenses, 14-45, 40-150, 50, 14-54. Of theses 14-54 is a definite winner followed by the 14-45 or the 40-150 (can't really make up my mind) and the brightest 50mm is the clear looser of the game, especially if end to end movement is necessary.

[Mikefellh]

Originally Posted by holidaydom People often comment that OLYMPUS cameras focus slowly, but what actually contributes most to the speed at which the camera is able to lock focus?

If they are using the kit lenses, what do they expect? Having tried every lens in Olympus' collection with my E-300 last summer, I have to say that it's dependent on the lens used, and it's focusing motor speed. We should see more improvement with SWD lenses.

[holidaydom]

Originally Posted by OlyFlyer Definitely the focusing motor speed is the most important factor. F-number of the lens has nothing to do with it. The ED 50mm is f2.0 and thus it should be the fastest to focus. The 14-54 is f3.5 at 54mm but it definitely focuses much faster. Of course, if you don't care about composition and can accept to focus anywhere, it would be better if we had a few hundred focusing points of cross type, but according to me, the center is fast enough with a good (speedy) lens motor. Algorithm and processing speed has nothing to do with it, since it is anyway far too fast for our brains. I have no idea about the difference between a "normal" motor and SWD, I have four Oly lenses, 14-45, 40-150, 50, 14-54. Of theses 14-54 is a definite winner followed by the 14-45 or the 40-150 (can't really make up my mind) and the brightest 50mm is the clear looser of the game, especially if end to end movement is necessary.

I think the ZD 50mm focuses slowly cos it's a macro lens - all macro lenses tend to focus slowly don't they?

What I ment by a lens with a bigger aperature being able to focus "faster" is that all things being equal (subject, lens motor, camera body); a larger aperature lens allows more light into the camera and the focus sensors will have more light to work with when focusing.

This ties in with the observation that focusing tends to take longer in dim light...

[holidaydom]

Can someone with all the cool gear test out the focusing speed of the ZD 14-54mm f2.8-3.5 on the following bodies...

1) E1
2) E500/E330 (or similar generation camera)
3) E410/E510

Are the focusing speeds noticably different?

I think a possible and quick way to test would be to manually focus the lens to infinity, switch to S-AF then point at a standard subject and snap the lens into focus; Keeping the camera on a tripod and in the same lighting...

A quick and dirty test but it may yield interesting results...

[marky]

Originally Posted by holidaydom Can someone with all the cool gear test out the focusing speed of the ZD 14-54mm f2.8-3.5 on the following bodies... 1) E1 2) E500/E330 (or similar generation camera) 3) E410/E510 Are the focusing speeds noticably different? I think a possible and quick way to test would be to manually focus the lens to infinity, switch to S-AF then point at a standard subject and snap the lens into focus; Keeping the camera on a tripod and in the same lighting... A quick and dirty test but it may yield interesting results...

Hmmm.. you should have suggested this during the kopi session when all the camera models are there. haha..

[OlyFlyer]

Originally Posted by holidaydom I think the ZD 50mm focuses slowly cos it's a macro lens - all macro lenses tend to focus slowly don't they?

That's just half of the truth. The other half is that the focus motor in it is definitely the slowest of all my lenses.

Originally Posted by holidaydom What I ment by a lens with a bigger aperature being able to focus "faster" is that all things being equal (subject, lens motor, camera body); a larger aperature lens allows more light into the camera and the focus sensors will have more light to work with when focusing.

If all things would be equal except the maximum aperture of a lens than I think it would not make any difference at all. Aperture opening has nothing to do with how fast the motor rotates.

Originally Posted by holidaydom This ties in with the observation that focusing tends to take longer in dim light...

I think that observation is based on some erroneous facts. To do the proper test you need to use identical cameras, objects and lighting. If the aperture is too small in the lens, the camera may have problems to find and lock focus, and would start to hunt. That means it missed the focus but it is not slow. Maybe slow to lock focus, you may say. But if you point the lens at a contrasty object (still under the same light) that should not be a problem. In fact, I never understood people complaining about the problems of low light focusing. I never experienced that problem. Of course, for a bright lens it is easier, but definitely not a problem if you aim at the right point.

I think that is also the understanding Olympus and other lens manufacturers have. That is why SWD and USM is invented.

[schon]

Originally Posted by OlyFlyer Algorithm and processing speed has nothing to do with it, since it is anyway far too fast for our brains.

just a thought: essentially all AF systems are fast if they do not hunt. even lenses with relatively slow motors (perhaps those in our kit lenses?). so if we actually had an AF system with a near-perfect algorithm - one that does not require hunting, wouldn't that greatly increase AF speed? instead of having a supersonic motor to make up for this deficiency?

[OlyFlyer]

Originally Posted by schon just a thought: essentially all AF systems are fast if they do not hunt. even lenses with relatively slow motors (perhaps those in our kit lenses?). so if we actually had an AF system with a near-perfect algorithm - one that does not require hunting, wouldn't that greatly increase AF speed? instead of having a supersonic motor to make up for this deficiency?

No, actually not. Our kit zooms have far too slow motors. A proof of that is that I never managed to use C-AF on any moderate moving objects with the kit zooms. That is actually not a problem with the 14-54 which I find very fast to focus. I have done identical tests on identical subject and under almost 100% identical light conditions. The 14-54 definitely beats the 14-45 and when used on the very same camera, using the very same algorythm, if that would be a key factor than it would have worked.

Just read this non-scientific review of the 14-45 and the 14-54 comparision.

http://olyflyer.blogspot.com/2007/06...d-14-54mm.html

[drakon09]

Originally Posted by schon a near-perfect algorithm

No such thing exists...

[NMSS_2]

how nice if we can have AF limiter on camera body or lens for macro lenses.

how nice if we can have cam5000 for our AF sensor.

how nice if we can have more than 11 AF points.

am i asking too much???

[diCam]

Originally Posted by NMSS_2 how nice if we can have AF limiter on camera body or lens for macro lenses. how nice if we can have cam5000 for our AF sensor. how nice if we can have more than 11 AF points. am i asking too much???

Pay S$3,000++ ?

[holidaydom]

Originally Posted by NMSS_2 how nice if we can have AF limiter on camera body or lens for macro lenses.

Actually... if OLY is a "fully digital" system from the ground up - what's stopping a "soft" focus limiter function on the Camera Body?

I belive the camera is able to read where the lens is at along its focal length as that information is reflected in the EXIF. So a software controlled focus limiter actually sounds do-able...

Hey you! - Yea you, the OLY Tech/Software guy - are you reading this~!?!?

[MarcusK]

No much idea about this. But I do experience slow focusing when in low lighting area. Guess is the light sensitivity in the body.
Anyway, should have discussed this in the Kopi session leh...!!!
Got so many cam to test out!! hahaha...!!!

[bousozoku]

Originally Posted by OlyFlyer ... I have no idea about the difference between a "normal" motor and SWD, I have four Oly lenses, 14-45, 40-150, 50, 14-54. Of theses 14-54 is a definite winner followed by the 14-45 or the 40-150 (can't really make up my mind) and the brightest 50mm is the clear looser of the game, especially if end to end movement is necessary.

The 50mm takes a lot more to focus manually, also. It's not looser...it's quite tight.

So, what you're saying is that the non-macro lenses that have better low light capabilities focus faster. Is that right?

I use my 50-200mm and 14-54mm a lot and find that manual focusing is quick but trying to use auto focus for me is ridiculous because I'd lose most of my shots.

[OlyFlyer]

Originally Posted by bousozoku The 50mm takes a lot more to focus manually, also. It's not looser...it's quite tight.

It is a clear looser among my four ZD lenses when it comes to focusing speed.

Originally Posted by bousozoku So, what you're saying is that the non-macro lenses that have better low light capabilities focus faster. Is that right?

No. What I say is the only thing that matters is the motor in the lens. Not the aperture of the lens or the used algorytm.

Originally Posted by bousozoku I use my 50-200mm and 14-54mm a lot and find that manual focusing is quick but trying to use auto focus for me is ridiculous because I'd lose most of my shots.

That is very strange indeed. If you can focus lock as sharp as the lens than you must be really very fast, or often shoot with small aperture and have the dof working for your advantage. Sorry, I have problems to believe that, unless something is wrong with your lenses or camera. Even the slowest ZD focuses very fast. If you'd say you focus faster with an OM lens than the camera can focus with a ZD, I'd say that is possible, but not with the "fly-by-wire" manual focus. I don't know about the 50-200, but the 14-54 I have is really very fast.