Focus speed measurements of E-3

[OlyFlyer]

This thread is almost a copy of another one I started on DPR. Since not everybody follows more than one forum, I thought I will share this with you as well.

ZD14-54 f/2.8-3.5

There has always been a lot of negative discussion about how slow the E-3 focuses and so on. It is said to have the fastest focus dSLR, which may not be true but it is definitely very fast with the right lens. I don't have any SWD lens, but I wanted to test with what I have, so I did the following with the 14-54. It is really simple and very basic, but at least it gives an indication that those who say the AF is slow don't really know what they are talking about.

I measured using a sound recording software. A microphone was connected to my computer and the microphone was held to the lens, the focusing distance indicator window. I used S-AF + MF mode, single centre AF, small sensitivity selected, which is my normal use. I set the lens to infinity, and then aimed at something about as near as the lens can focus and half pressed the shutter release button. The lens motor is run in two steps almost all the time and shortly after the second fine adjustment the focus confirmation beep is heard. I recorded this 50 times. The average time it took was 0.7 seconds between the start of the first focus movement and the end of the second beep sound. Longest I measured was 1 second and the shortest was 0.4 s. All under bad lighting indoors. It is possible that there are cameras and or lenses which are faster, as I said I have no SWD, but to me an average of well below 1 second is fast enough.



This is the way it looks like on my screen. I wish I had access to SWD to make similar measurements, but from last week session, when I had a few DPR fellow forumers as guests in my house, I have a feeling the 12-60 is not really faster or if it is, it is only marginally.

ED50 f/2 Macro

The same test done with the ED50/2 this time. Again, the light is normal room, too dim for macro, and not my favourite for portrait. The thing I am aiming at is my keyboard, which is a DELL, which is black with white letters. Lens is manually forced to infinity than AF activated and the time to the double beep is measured from the time the focus motor starts to run. For this lens it is not a very good test since the lens takes some time to 'think' before it starts to turn. This time seem to be constant, but I have not measured, so I may be wrong. I must yet figure out a way to measure that time.



As you can see, the time is 1.15 seconds. My avargadge was actually a bit more, 1.29 seconds, but still fast enough.



This is what happens when my lens misses the focus. It goes all the way than back. Still only two seconds.

Of course, this is not an action lens at all, but I have used it to cover tennis using the E-500 I had and I had no troubles. One more thing about the history of my lens. I had a problem accepting hunting and sent it in to Oly after one week of owning this lens. The Oly Master 1 did not recognise the lens, but it seemingly worked, other than it was rally slow and often hunting. After the service, the lens was recognised by Master 1 and became much faster and stopped hunting. With the E-3 it occasionally hunts, but still fast to be a macro IMO.

I will continue with my other lenses, but I don't expect very high speed there. I only have the 17.5-45 and the 40-150 (old) so it is not so exciting.

[Oly5050]

Wow...amazing test. Good job on the methodology. Now all u need is an SWD.

[OlyFlyer]

Originally Posted by Oly5050 Wow...amazing test. Good job on the methodology. Now all u need is an SWD.

Thanks!

Just about a week ago I had an Oly meeting in my home and ahd the opprtunity to test the 12-60 but I did not test it because I will not buy that lens anyway. We will meet again and then I will try to spend a half an hour to make some recordings just to document even that lens.

I tested the 50-200 SWD last weekend though. One thing I noticed is that if you focus at for example 4 meters distance, take a shot and then aim at 50 meters the lens first went all the way to the nearest focus distance and then out to the aimed 50 meters. This was the case even if the distance difference between the present and the next focus was less. It is not like than with any of my lenses. I don't know if that is only the case with the 50-200 SWD or the old one behaved the same way, but it definitely slows dows the focusing quite a bit and I don't like that. Focusing was accurate and fast, but it could be even faster if it did not behave like that.

[splim]

Originally Posted by OlyFlyer ... I tested the 50-200 SWD last weekend though. One thing I noticed is that if you focus at for example 4 meters distance, take a shot and then aim at 50 meters the lens first went all the way to the nearest focus distance and then out to the aimed 50 meters. This was the case even if the distance difference between the present and the next focus was less. It is not like than with any of my lenses. I don't know if that is only the case with the 50-200 SWD or the old one behaved the same way,....

Unfortunately it is the same as with the old 50-200. If that happen, I usually stop and manually turn to infinity then refocus again.

[splim]

Originally Posted by splim Unfortunately it is the same as with the old 50-200. If that happen, I usually stop and manually turn to infinity then refocus again.

May be there is some formula in it, that, when the new focus distant is not within certain range and/or it's dimmer ?

[drakon09]

Aha! CoolEdit Pro!

Something I used to use on a daily basis.

[OlyFlyer]

Originally Posted by splim Unfortunately it is the same as with the old 50-200. If that happen, I usually stop and manually turn to infinity then refocus again.

This is bad news. Unfortunately, as it seems, it is alwasy like that with the 50-200 SWD I tested, not a 'when it happens' case. I don't know if that is the case with every SWD lens. Manually turning focus to infinity is I think slower than letting the AF motor do it's work, at least with the SWD.

[OlyFlyer]

Originally Posted by splim May be there is some formula in it, that, when the new focus distant is not within certain range and/or it's dimmer ?

I think the problem is quite logical if you think about it. When I aimed the second time after the lens was in focus, the image was so blurred, due to the distance difference and the large aperture, there was no way for the camera to know which way to go. It seems as in that case it always goes to nearst focus direction and than out to infinity. I don't know if it is solvable by some formula, I doubt that.

Another thing I found irritating with that lens was the zoom ring. I found it is hard to turn, causing the camera to be twisted as well. Maybe one can get used to it, but I don't understand the reason.

[Oly5050]

Just took out my 35 mm and played with it. I am not sure, but it did seem like the 35 mm focuses faster than the 50 mm f2.0. I did a focus at about 3-4 m, and then again at about 10cm, it was like zip and it was there. And this was all in warm fluorescent room light.

[OlyFlyer]

Originally Posted by Oly5050 Just took out my 35 mm and played with it. I am not sure, but it did seem like the 35 mm focuses faster than the 50 mm f2.0. I did a focus at about 3-4 m, and then again at about 10cm, it was like zip and it was there. And this was all in warm fluorescent room light.

I believe in that situation every lens focus very fast since the distance difference is very short. Try to set the lens to infinity and then aim at something at the closest distance. Of course, it is possible the 35mm is faster, but IMO 1.2 sec end to end time is not bad.

As for the low light, I think it is just a myth that it would be a problem. As long as it is not really dim and you aim at a contrasty spot, I found it always works. Not only with the E-3, but it also worked well with the E-500 I previously had.

[viewwing]

I guess most of the focussing speed has to do with the understanding of how DSLR does its auto focussing.

If we can find contrast it will almost always lock one the very first time.

Great test flyer

[OlyFlyer]

Best result is 1.122 seconds.




Worse result is 2.034 seconds.



I measured an avaradge of 1.39 seconds, which considering this is the cheapest kit zoom, not a bad value. Again, it is not the light intensity but the contrast in the image which make the fast focus possible.

[wong_se]

kudos to OlyFlyer.
this is great contribution.