PMW-EX1 Auto Focus Slow?

[Leonard Levy]

This is all pretty typical with 24 progrssive on all the cameras isn't it. Not very good on the HVX either- lots of hunting.

[Steven Thomas]

Any more on this?

There's times my camera will not even lock onto focus at all.
No, I'm not shooting a bare wall ;), this is aiming right at well lit high
contrast objects.

[Thierry Humeau]

Auto focus is indeed slow on the PVW-EX1 and I have no intend to use it as the manual focus ring is probably one of the primary reason I liked the EX. It works well but it takes a lot of turning to go form closeup to infinity and it is not quite as smooth as a 15K HD lens. That said, people who have struggled manual focusing on the Z1 or HVX-200 will be very pleased.

I feel there is something inerant to motion pictures acquisition that will never allow autofocus systems to work well. Take for exemple a "rack focus", there is no way a computer chip will ever figure this one out.

Thierry.

[Thierry Humeau]

And I forgot to mention the iris ring, even better than the focus one. Smooth, no stair stepping, very fine control of your exposure. Again, as for focusing, I rarely use auto iris.

Thierry.

[Evan Donn]

Originally Posted by Thierry Humeau

I feel there is something inerant to motion pictures acquisition that will never allow autofocus systems to work well. Take for exemple a "rack focus", there is no way a computer chip will ever figure this one out.

Perhaps - but maybe that's just because having a computer drive an electric motor which moves a complex mechanical lens system to try and focus an image that the computer can't see or understand is the wrong approach. A better approach would be to not have to worry about focusing at all while we're shooting - let the computer deal with focus in post so that we can keyframe things like racks or track moving subjects.


It sounds a little 'sci-fi'... until you've seen this: http://graphics.stanford.edu/papers/lfcamera/
(make sure you watch the video: http://graphics.stanford.edu/papers/...a/lfcamera.avi)

Now that your mind is suitably blown, back to the EX. I suspect the slow autofocus is simply the price we have to pay for having a true mechanical lens - it's got to be much easier to make a fast, smooth and quiet autofocus when you don't have to have the lens elements coupled to gears meant to be turned by a large outer ring.

[Malcolm Hamilton]

For me, this news about the slow auto-focus is certainly bad news. I might get no sympathy from most of you on this forum - - you're talented camera operators who love (and deserve) the manual zoom, manual iris, etc.. But I'm just coming to camera work (from producing, directing and editing), and I've been using autofocus almost exclusively (with the Sony Z1U) for the last five months. So, why don't I get stick with the Z1U, or get another camera like it, with a cheaper lens (that can autofocus)? Maybe I should. But I really wanted to get away from tape-based shooting, and I like the fact that the EX1 can shoot in lower light levels (requiring less lighting, another area I feel inadequate in).
Any advice? Is the autofocus on the EX1 so bad as to make it essentially UNUSEABLE?
Let me add this about how I shoot, in case I could get by with manual focus (and just don't know it) - - for most of the shooting I do, I seldom zoom... I usually stay zoomed out (if I want a tighter shot, I move closer). Would this simplify things for me, re focusing?
If people here advise me to NOT get the EX1, is there another camera you would suggest (flash-card based; able to shoot in low light, etc.)
Thanks,
Malcolm

[Craig Seeman]

Malcolm, btw I'd been editing nearly 20 years before I started shooting so I do know where you're coming from.

When using my PD-170 I relied on Push Auto since trying to deal with that servo controlled ring was a pain. Having "full manual" control is a blessing. I can focus fast since the ring allows me to.

That said, there is a variety of different "auto focus" situations so the camera response may not be "equal" in all those situations.

It may be one thing to move from one object to another in different focal planes. That might be slow for this camera to respond.

It's another to track a single subject changing the focal plane.

In other words, tracking a single moving object may be different than switching objects, so I'd test those two circumstances separately.

There's also lighting/contrast as a factor and the speed at which it change may be affected by that too.

Think about how the auto focus works and discerns the subject.

So the tests (that I can think of)
high contrast tracking a subject
low contrast tracking a subject
high contrast changing a subject
low contrast changing a subject
one might also try auto always on vs manual with push auto.

[Jon Nelson]

This EX1 autofocus news is BAD

Focus is my #1 issue in HD

Coming from big cameras with real (& expensive) viewfinders with which we have a hard enough time "estimating" focus... the small cameras with really inferior monitoring and often using them at arms length from our eyes and usually not in the best lightning conditions... well, autofocus that works is a great (necessary) tool!

A 2" viewfinder on the big cameras just can't cut it for HD focus. Heck in Sd the producer would look at the 8" CRT and say "it's soft". Now in HD we need a 17" or 24" display to even estimate what it will look like on a 42" or larger panel to the viewers at home

For us, the small cameras are a different tool than the big cameras - with the small format you can shoot in styles that the big cameras can't, they are just too big. But, autofocus is critical in these fast, documentary style, handheld situations

The HVX200 autofocus was/is a joke. The Canon A1/G1 autofocus works incredibly well! To think we'll take a huge step backwards in autofocus with the EX1 is not good news!

[Malcolm Hamilton]

thanks, Craig, for your reply.
I can't test the camera out, as I don't have one (I was on the verge of buying one, when I saw this thread)... but I hope others, who do have the camera, continue to weigh in on this.
I'm concerned because of what Steven Thomas, says, i.e. - -
”There's times my camera will not even lock onto focus at all”

... to me, that means the autofocus is unuseable!

But then, Leonard Levy says:
“This is all pretty typical with 24 progrssive on all the cameras isn't it. Not very good on the HVX either- lots of hunting”

... does this mean that if I shoot 30 fps, autofocus might work better?
Thanks,
Malcolm

[Craig Seeman]

Jon, you apparently haven't used the LCD with with the EX1. It's beyond anything I've seen in detail on a camera LCD. With both Expand Focus and Peaking as a choice (and while in record too) I can nail focus pretty fast in full manual.

Originally Posted by Jon Nelson

This EX1 autofocus news is BAD

Focus is my #1 issue in HD

Coming from big cameras with real (& expensive) viewfinders with which we have a hard enough time "estimating" focus... the small cameras with really inferior monitoring and often using them at arms length from our eyes and usually not in the best lightning conditions... well, autofocus that works is a great (necessary) tool!

A 2" viewfinder on the big cameras just can't cut it for HD focus. Heck in Sd the producer would look at the 8" CRT and say "it's soft". Now in HD we need a 17" or 24" display to even estimate what it will look like on a 42" or larger panel to the viewers at home

For us, the small cameras are a different tool than the big cameras - with the small format you can shoot in styles that the big cameras can't, they are just too big. But, autofocus is critical in these fast, documentary style, handheld situations

The HVX200 autofocus was/is a joke. The Canon A1/G1 autofocus works incredibly well! To think we'll take a huge step backwards in autofocus with the EX1 is not good news!

[Kit Hannah]

Just for reference here...

What other "professional" lens has Auto Focus anyways? This is a real Fujinon Lens for the most part and there are going to be some drawbacks when trying to integrate consumer or prosumer grade features into a camera of this caliber. Personally, I would have rather they left off the AF completely, because when dealing with other professional cameras, its not typically going to be an option. I understand that the EX1 was made in the smaller form factor, but for people used to a professional camera and lens, AF being a bit slow is not a big problem. It will probably only create issues for people stepping up from lower end cameras.

[David Elkins]

Originally Posted by Kit Hannah

Just for reference here...

but for people used to a professional camera and lens, AF being a bit slow is not a big problem.

My thoughts exactly, I have rarely, if ever, used AF on the DVX100 I bought years ago I am so used to all manual lenses. This is by no means a deal breaker for me. But, does the EX1 have a push auto function? I have used that a few times and found it handy when my eyes get screwed up from wind or salt water.

[Evan Donn]

Originally Posted by Jon Nelson

A 2" viewfinder on the big cameras just can't cut it for HD focus. Heck in Sd the producer would look at the 8" CRT and say "it's soft". Now in HD we need a 17" or 24" display to even estimate what it will look like on a 42" or larger panel to the viewers at home
...
The HVX200 autofocus was/is a joke. The Canon A1/G1 autofocus works incredibly well! To think we'll take a huge step backwards in autofocus with the EX1 is not good news!

I have an A1 and I've never tried the autofocus. However, I don't use an external monitor and I've never had trouble focusing on the LCD with peaking turned on - and from everything I've read here the LCD on the EX is far better, as is peaking, than on the A1. I can't imagine it's going to be difficult to focus. In either case, I'd rather have a whole shot look a little soft than risk have the autofocus hunting in the middle of a shot.

[Malcolm Hamilton]

Originally Posted by Kit Hannah

It will probably only create issues for people stepping up from lower end cameras.

I hear what you're saying, Kit (and other contributors, like Evan, seem to agree that for pro users, poor autofocus isn't going to be a problem). If you don't mind, though, now I'm wondering how tricky it might be for me to get the hang of manual focus, and I'd love any advice. As I say, I'm a bit new to shooting - - I realize this perhaps means I should stick with the Z1, but I'd like to upgrade for the reasons I gave before (mostly: sick of tapes & want to get into editing faster; also, want to do less lighting).

I'd love know how hard it would be for me to learn to focus manually... I'd hate to start messing things up by shooting soft... Is the EX1 display so good (people are raving about it) that this is unlikely?
And here's my other question again (sorry if it sounds a bit silly) - - the fact that I mostly shoot with the lens zoomed out completely (if I want a tighter shot, I move closer) - - would this make it easier for me to stay in focus, in manual? (I realize that if I want to shoot someone walking towards the camera from 50 feet away, I'd have to be changing focus as they approach and pass me; but if I'm walking along beside them, if I stay zoomed out, I shouldn't have to adjust the focus, right?)
Thanks for your patience,
Malcolm

[Steven Thomas]

I've been waiting for more info regarding the AF, hence this thread.

This question stems from the possibilty that there is something wrong with my camera. Now, I'm starting to wonder if this is across all EX1 cameras. From using other cameras, I know that AF can be questionable most of the time. Due to the nature of AF sampling, you need to use a higher frame / shutter rate. Using interlace, since two fields roll by per given frame, it tends to work the best. Therefore, ideally 720 60P or 1080 60i should be selected.

Having said that, here's what i've found with the PMW-EX1. Even if the camera is stationary and aimed at good high contrast structures, it will not lock and rest. It breathes (pulses) in and out at a steady rate.

I'm not sure how Sony has setup the AF matrix, 5 point, center weighted, full field matrix, etc, but it's apparent that it needs to be tweaked. I would believe firmware could accomodate this problem. Once it locks on its strongest peaking, it needs to stop servo. It could be their AF servo window is small. Once the camera sees it highest peak, they probably need to open the limits up just a bit.

To test for what I'm seeing.

1. Set you camera on a tripod under adequate light.
2. Set the camera to 1080 HQ 60i (1/125) or 720 60P (1/125)
3. Slide the lens to AF/MF away from body.
4. Slide AF switch on side if lens to "Auto" position. (Full AF is now on)
5. Turn menu option "MF Assist" OFF.
6. Turn ON "display info" to show DOF LCD display.
7. Turn ON "Peaking" and set its menu Level setting to "high".
The last two steps will aid in watching the AF problem.
8. Set the camera/tripod about 10' from your zoom in a bit and allow the camera to focus on your high contrast objects.

In my case, you can watch it pulse in and out of focus for about 8 seconds or longer. NOW, if you turn ON the "MF ASSIST" menu option and readjust to make the AF system work again, It will pulse almost continually and never stop.

If you shut off the the AF switch to "MANU" manual position, this allows the camera to be in manual / AF with the option to press the bottom AF push button for auto focus assist. Now, using this switch it starts to auto focus continually pulsing in and out just like the full auto focus mode.

Please try the above test.

Even using the camera under normal wide conditions when your doing run-and-gun, even with the wide DOF you can watch the focus breathe. Using the LCD DOF lens info feature, you can waych that bounce around while the AF pulses.

I know AF has never been that great on a lot of cameras, I know, I've used them. My concern is with the continuous pulsing issue.

I known a lot of users, including myself never use AF. But, this should at least work to some degree. I understand hunting when there's moving images, but when capturing with the camera not moving shooting stationary objects with good light and good contrast, this should "lock" servo, not pulse.