Thoughts on the GH2's tele conversion feature

[tflak]

I wouldn't think the amount of "zoom" produced by the tele conversion should be a factor at all. After all, as I understand it, it's a 1:1 crop of the sensor's image as seen through the lens at whatever the actual zoom or focal length of the lens is at the time. The processing is taking place after the image is captured by the sensor, right? So a 20mm (40mm, 35 equiv) should actually be a 104 using the tele conversion, but have the same stability as the 20mm (40mm, 35 equiv). No?

The only thing I'm concerned about is image quality. I know that, theoretically, it should be fine, but I won't believe it until I see it.

 

[tflak]

No I don't think so... If you take the 20mm or any lens for that matter and use the focus assist, you can see what I mean.

Good point, but I dunno...the focus assist is a digital zoom, not a crop of the sensor.

 

[thisisapocalypse]

I wouldn't think the amount of "zoom" produced by the tele conversion should be a factor at all. After all, as I understand it, it's a 1:1 crop of the sensor's image as seen through the lens at whatever the actual zoom or focal length of the lens is at the time. The processing is taking place after the image is captured by the sensor, right? So a 20mm (40mm, 35 equiv) should actually be a 104 using the tele conversion, but have the same stability as the 20mm (40mm, 35 equiv). No?

The only thing I'm concerned about is image quality. I know that, theoretically, it should be fine, but I won't believe it until I see it.

The portion of the image circle used in 1:1 mode would be just as stable as that portion of the image circle when it's covering the full sensor, but part of what makes a 20mm image fairly stable when handheld is that you're covering a very wide field of view and the effects of slight movement/shake are less magnified due to the wide FOV - while there will probably be less shake/movement when using a 20mm lens at 1:1 crop of the sensor than if you were using a tele lens with a 104mm equivalent FOV, the effects of movement are going to still going to be magnified. There's no doubt a wide lens at 1:1 crop will behave differently than a real telephoto lens would act when covering the full sensor, but there's no way that it won't be shaky (or even close to as smooth as when using a 20mm on a full sensor) if you don't stabilize the camera somehow when you're in 1:1 mode.

 

[pomoville]

I wouldn't think the amount of "zoom" produced by the tele conversion should be a factor at all. After all, as I understand it, it's a 1:1 crop of the sensor's image as seen through the lens at whatever the actual zoom or focal length of the lens is at the time. The processing is taking place after the image is captured by the sensor, right? So a 20mm (40mm, 35 equiv) should actually be a 104 using the tele conversion, but have the same stability as the 20mm (40mm, 35 equiv). No?

The only thing I'm concerned about is image quality. I know that, theoretically, it should be fine, but I won't believe it until I see it.

nope, because the shake is being magnified as well. Say the camera jumps 10 pixels to the left while you're recording. With the 2.6x zoom, the image would shift 26 pixels to the left. This is why you need to stick to 35mm standards for shutter speed (e.g. at least 1/100 of a second on a 50mm lens (equivalent of 100mm on full frame.)

 

[tflak]

The portion of the image circle used in 1:1 mode would be just as stable as that portion of the image circle when it's covering the full sensor, but part of what makes a 20mm image fairly stable when handheld is that you're covering a very wide field of view and the effects of slight movement/shake are less magnified due to the wide FOV - while there will probably be less shake/movement when using a 20mm lens at 1:1 crop of the sensor than if you were using a tele lens with a 104mm equivalent FOV, the effects of movement are going to still going to be magnified. There's no doubt a wide lens at 1:1 crop will behave differently than a real telephoto lens would act when covering the full sensor, but there's no way that it won't be shaky (or even close to as smooth as when using a 20mm on a full sensor) if you don't stabilize the camera somehow when you're in 1:1 mode.

Makes sense, thanks for the explanation. My saying it shouldn't be a factor at all was way off the mark. Movement is movement and magnification is magnification. No way to get around that. What I'm having a hard time wrapping my head around is just how much differently it will behave. Guess the only way to know is to wait and see.

 

[thisisapocalypse]

It will be interesting for sure - it's going to be interesting to use a 20mm lens yielding a FOV of a 104mm lens (35mm equivalent). It seems like it will be best to stick to using the full sensor for most shots, but there will be some cool uses for the tele mode. I don't see a great reason to use something like the Panny 20mm pancake, but using superwides designed for 16mm film could be interesting and particularly some of the fast 16mm/tv zooms - being able to shoot at somewhere between 400-800mm+ FOV (35 equiv) and beyond with the light gathering capability of some of the fast tv zooms could be really cool for certain things and definitely nature videography.

Conversely if you have a moving shot/subject, you could put on something like the 11-16mm Tokina and at the wide end you'd end up shooting at about a 50mm FOV (35mm equivalent) but with a tooooooon of depth of field even wide open. This could be useful for moving camera/steadycam shots if you don't have a focus puller. But that will only be good for certain kinds of shots - shooting in such a small image area, you'll have very little control over DOF, it's always gonna be pretty deep. But it does give us more options which is never a bad thing and I'm sure people on this board will find some really good uses for it.

 

[raymondluo]

Looking at the discussion thus far, i'm wondering if the planned 25mm F1.4 Lumix will have MEGA O.I.S in it. It makes sound sense for it to be Leica endorsed and while typical normal focal length lenses would typically not have IS, having the technology would certainly break away from the market and offer a unique selling point from the competing system lenses as well as draw a distinct bridge from the Voigtlander 25m 0.95.

Being able to shoot at a lower shutter speed (for photography), image stabilization during video, image stabilization during tele-conversion (for a truly useful 'tri-lumix') + AF/ C-AF almost certainly an instant hit for photo-videographers and will not affect Voigtlander sales either, their target audience being rather different.

It is obvious Panasonic is serious about videography as much as it does photography with much of it's technology interchangeable between video and photo so I hope this isn't just a wish list, but a prediction of what's to come. Meanwhile the 20mm 1.7 will be my beater.