No Autofocus on HD100?
- Thread starter razamalik
- Start date
Flintstone
Well-known member
Ouch! :shocked:
Actually I've always wondered why most professional cameras don't have a near infrared system implemented... Of course this could be due to the filter over the CCDs. Still I imagine it would be useful for those doing run n' gun stuff. There's nothing quite like seeing in the absolute dark without gain.
Barry_Green
Moderator
Autofocus is a *very* handy option to have, especially when shooting HD. Those who are saying "no pro would ever use autofocus" should consider if they've ever shot HD, and most especially if they've ever shot HD while using a 200,000-pixel viewfinder. This isn't a standard-def camera with a CRT viewfinder we're talking about!
Nobody's saying you'd leave the camera in autofocus. But the ability to zoom in, swap to AF, let the camera lock in, and then turn back to manual, is a handy option to have, and given the low-res LCD finders on these cameras, AF is likely to pinpoint focus more accurately than manual focus would. The camera's internal electronics have a lot more information to make a decision on, vs. the low-res LCD viewfinder the manual-focuser gets his/her info from. Of course, it's possible that the expanded-focus and 1-for-1 pixel mapping will help get more accurate focus, but why turn down the option if you don't have to? You can always choose to use it or not use it. Beats getting out-of-focus footage...
Obviously if you're in a tracking environment, lots of motion etc., autofocus isn't going to work. But pro SLR still cameras are using autofocus all the time now. Autofocus itself isn't "bad", it's a great invention, the only thing "bad" about it is when someone uses it improperly.
And it's always better to have the option, and choose not to use it, than to never have the option and need it.
Nobody's saying you'd leave the camera in autofocus. But the ability to zoom in, swap to AF, let the camera lock in, and then turn back to manual, is a handy option to have, and given the low-res LCD finders on these cameras, AF is likely to pinpoint focus more accurately than manual focus would. The camera's internal electronics have a lot more information to make a decision on, vs. the low-res LCD viewfinder the manual-focuser gets his/her info from. Of course, it's possible that the expanded-focus and 1-for-1 pixel mapping will help get more accurate focus, but why turn down the option if you don't have to? You can always choose to use it or not use it. Beats getting out-of-focus footage...
Obviously if you're in a tracking environment, lots of motion etc., autofocus isn't going to work. But pro SLR still cameras are using autofocus all the time now. Autofocus itself isn't "bad", it's a great invention, the only thing "bad" about it is when someone uses it improperly.
And it's always better to have the option, and choose not to use it, than to never have the option and need it.
Barry_Green
Moderator
In the past that has been true, but it doesn't need to be. You can get 100% control over the ring, and 100% accurate distance readouts in the viewfinder. You may not have markings on the lens barrel, but you'll have distance markings in feet and in meters in the viewfinder (which is different from the "old way", but better too, as you don't have to pull the camera away from your eye to look at the lens barrel).mezelf27 said:
Barry_Green
Moderator
It is possible to have the best of both worlds -- that's what you'll get on the HVX.
Using servos means that there's not a direct mechanical linkage between the lens ring and the inner elements of the lens. On servos like the PD150 and XL1, the ring is actually a motor switch that triggers the lens' internal motors to start moving. How much you move the ring, and how fast you move the ring, are not directly related to how the lens elements move. Same is true of the zoom ring on the FX1 and Z1 -- you can move the zoom ring very quickly, and the lens won't be able to keep up.
And, unless the ring moves when the autofocus moves, the position of the ring changes relative to the position of the lens elements when you go into autofocus mode. For example, let's look at the Z1's zoom ring. You can manually zoom all the way out, so the zoom ring says 4.5mm. Then when you switch to motorized/servo zoom, you can zoom all the way in -- but the zoom ring doesn't move, it still says 4.5mm! So the markings don't reflect what's actually going on in the lens. (switch back to manual and the lens elements will quickly do a power-zoom out all the way, so they re-align with the markings).
Now contrast that with the DVX and HVX -- the zoom rings are mechanically linked to the inner workings. The zoom ring will always match exactly with what the inner elements are set to.
As for focus, the servo cameras are using the focus ring as a sort of on/off switch for the focus motor. It's not unlike the zoom toggle, except it's a circular ring instead of a toggle switch, but the basic principle is the same. The DVX and HVX are a little different. Because they have autofocus, they don't use the same mechanical linkage that they do for zoom. But they're not just motorized servo switches either. Their rings are position-dependent, and moving the ring at a certain speed or certain distance will result in 100% repeatable movement of the inner lens elements. They're not completely mechanically linked to the inner workings like the zoom ring is, but they're still precise, repeatable, and position-dependent -- something you can't say about PD150 or XL1 zoom rings or focus rings.
Furthermore, the DVX gives a readout of where the lens element is -- i.e., at what point through its focus range it's set at (the familiar MF00-MF99 scale). Not quite the same thing as lens barrel markings in feet or meters, but just about as functional, if in a different way. The HVX improves on that by giving you the distance scale, as well as giving you actual feet measurements, and actual meters. So you get a precision manual focus ring, with repeatable focus marks, that tells you exactly what feet or meters it's set to.
Plus autofocus.
The best of both worlds.
Using servos means that there's not a direct mechanical linkage between the lens ring and the inner elements of the lens. On servos like the PD150 and XL1, the ring is actually a motor switch that triggers the lens' internal motors to start moving. How much you move the ring, and how fast you move the ring, are not directly related to how the lens elements move. Same is true of the zoom ring on the FX1 and Z1 -- you can move the zoom ring very quickly, and the lens won't be able to keep up.
And, unless the ring moves when the autofocus moves, the position of the ring changes relative to the position of the lens elements when you go into autofocus mode. For example, let's look at the Z1's zoom ring. You can manually zoom all the way out, so the zoom ring says 4.5mm. Then when you switch to motorized/servo zoom, you can zoom all the way in -- but the zoom ring doesn't move, it still says 4.5mm! So the markings don't reflect what's actually going on in the lens. (switch back to manual and the lens elements will quickly do a power-zoom out all the way, so they re-align with the markings).
Now contrast that with the DVX and HVX -- the zoom rings are mechanically linked to the inner workings. The zoom ring will always match exactly with what the inner elements are set to.
As for focus, the servo cameras are using the focus ring as a sort of on/off switch for the focus motor. It's not unlike the zoom toggle, except it's a circular ring instead of a toggle switch, but the basic principle is the same. The DVX and HVX are a little different. Because they have autofocus, they don't use the same mechanical linkage that they do for zoom. But they're not just motorized servo switches either. Their rings are position-dependent, and moving the ring at a certain speed or certain distance will result in 100% repeatable movement of the inner lens elements. They're not completely mechanically linked to the inner workings like the zoom ring is, but they're still precise, repeatable, and position-dependent -- something you can't say about PD150 or XL1 zoom rings or focus rings.
Furthermore, the DVX gives a readout of where the lens element is -- i.e., at what point through its focus range it's set at (the familiar MF00-MF99 scale). Not quite the same thing as lens barrel markings in feet or meters, but just about as functional, if in a different way. The HVX improves on that by giving you the distance scale, as well as giving you actual feet measurements, and actual meters. So you get a precision manual focus ring, with repeatable focus marks, that tells you exactly what feet or meters it's set to.
Plus autofocus.
The best of both worlds.
Well, the problem is just it is speed-dependend...
If it wasn't it was easier repeatable. Anyhow: I get your point that AF should be sharper than what you could see in a low-res viewfinder, but if the AF isn't 100% spot-on, and you lock the focus point anyway, you won't see it either.
You have the new focus assist stuff for this. I don't know. Perhaps it's a matter of taste. But before I bought my XL1 I thought: well AF, that could come in handy.... But at the end of the day I just have to admit I never used it (well, I cursed it quite a few more times, due to the weird manual control on that lens)...
If it wasn't it was easier repeatable. Anyhow: I get your point that AF should be sharper than what you could see in a low-res viewfinder, but if the AF isn't 100% spot-on, and you lock the focus point anyway, you won't see it either.
You have the new focus assist stuff for this. I don't know. Perhaps it's a matter of taste. But before I bought my XL1 I thought: well AF, that could come in handy.... But at the end of the day I just have to admit I never used it (well, I cursed it quite a few more times, due to the weird manual control on that lens)...
Barry_Green
Moderator
I definitely agree about the XL1 lenses. On that camera, the tradeoff wasn't worth it. The manual lenses were sweet, the auto lenses were infuriating.
The HVX is supposed to be the best of both worlds.
The HVX is supposed to be the best of both worlds.
Barry_Green
Moderator
The HD100 has about 230,000 pixels on its viewfinder, 250,000 on its LCD. That's pretty good for a DV camera (even though the DV frame is about 350,000 pixels), but considering the HDV 720p frame has almost 1 million pixels, that definitely qualifies as "low res". The viewfinder/LCD is having to scale the image down by a factor of 4. The HD100 has a superb "peaking" feature which will definitely help with focus, but it's not nearly like having a full-res display. The viewfinder is removable, and presumably you could susbstitute in a real HD viewfinder, but considering those start at around $4,000 I don't think it's a likely option for too many people.
Specs on the HVX's LCD are not available yet, but they should be similar (230k-250k). The HVX allows a "focus assist" mode that shows a pixel-accurate 1:1 extraction, so you can see the center of the frame at full resolution, for pinpoint focus accuracy.
Specs on the HVX's LCD are not available yet, but they should be similar (230k-250k). The HVX allows a "focus assist" mode that shows a pixel-accurate 1:1 extraction, so you can see the center of the frame at full resolution, for pinpoint focus accuracy.
Barry_Green
Moderator
I'm saying that the focus assist function on the JVC works very, very differently. It doesn't magnify anything. Instead it does a wild color solarization effect. I only played with it for about five seconds so I don't know exactly what it was supposed to do, but it seems like it's posterized peaking on steroids.
But no, as I observed, no pixel-for-pixel magnification like the HVX (and the FX1/Z1) do.
But no, as I observed, no pixel-for-pixel magnification like the HVX (and the FX1/Z1) do.
videoteque73
Active member
It's true that focus with just an LCD preview is a bad thing. But I don't think autofocus solves anything, how can the camera know WHERE do you want to focus??
The JVC assist focus works very well. I played with it for more than five seconds :thumbsup: and I can tell that it gives you information about where the focus is. It works, at least to prepara the focus. I don't know if it works while recording...
The JVC assist focus works very well. I played with it for more than five seconds :thumbsup: and I can tell that it gives you information about where the focus is. It works, at least to prepara the focus. I don't know if it works while recording...
...Yeah, just looked at my first ever Sony Handycam (going way back to when I was 12) and that had AF and a real fixed manual focus too...
It had (well still has) an amazing macro: it can focus on things touching the lens!?! Didn't know that was possible... arrrr the good old days!
It had (well still has) an amazing macro: it can focus on things touching the lens!?! Didn't know that was possible... arrrr the good old days!