New Panasonic AG-AC90

[Peter Copestake]

Impressions of this camcorder, when anyone can lay hands on one, would be much appreciated.
Looks good to me but I'm clueless about the sensors especially. Comparisons with Canon XA 10 particlarly.
http://business.panasonic.co.uk/profess ... am/ag-ac90
Peter.

[tom hardwick]

Not put my hands on one Peter, but it's the TRV900 / PD100 or VX2000 / PD150 link-up I reckon. Panasonic found they had a real winner on their hands with the SD700 then the SD900 and now the X900, but all these cameras are 'consumer' cams in that you couldn't (easily) attach proper microphones to them.

So up pops this AC90, and it's a 900 with XLR connectivity. All the rest is consumer spec: three ¼'' CMOS chips, hybrid OIS, 12x f/1.5 zoom, no switchable ND filters and so on. This is the Sony PD100 to the consumer's TRV900.

tom.

[TimStannard]

So up pops this AC90, and it's a 900 with XLR connectivity. All the rest is consumer spec:

Indeed, but the spec of a very good consumer cam PLUS what looks like two control rings and manual buttons for easy access to manual functions. All things that have been missing for a while in consumer cams and all things which put me off buying a 300/700/900 series Panasonic to replace my Standard Def NV-GS400 (which has a small selection of manual control buttons, but enough to make me consider only having menu controls too limiting)

Obviously I'd like an HMC151, but that's not going to happen - at least not in the same universe as my marriage surviving

[Peter Copestake]

Yes, Tim, it was the three control rings and the actual buttons rather than touch screen that made me think it might be better than the Canon but I hadn't noticed the lack of N/D filters that Tom pointed out whichis just the sort of thing that I needed more expert comment on.
In the less intense light of Lancashire the stronger N/D filters don't see much use and I might not miss them. There isn't usually time to think about differential focus in my work/play which is concerned with capturing reality rather than artistic effect so again their absence might not be noticed.
I have been promised hands-on opportunity as soon as they come in (October 1st) so will post my inexpert impressions here.
Thanks both Tom & Tim.
Peter.

[tom hardwick]

Peter, the AC90 will have internal (undocumented) NF filters, just as the 700/900 does, and as Tim's GS400 does. If the light gets too bright and the camera has to resort to apertures smaller than about f/5.6, then the shutter speed will be shortened from the default 1/50th sec to soak the light. So you may want to lock the shutter to 1/50th and add external ND, though I wouldn't recommend this route on a camera with such a very short focal length lens.

I'm guessing the AC90 will act in the same way as the 700/900 series, i.e. the lens will stay at maximum aperture for as long as possible, altering the exposure with the internal ND. This will indeed give you the least dof, so your artistic shots might come to you unasked.

tom.

[TimStannard]

I have been promised hands-on opportunity as soon as they come in (October 1st) so will post my inexpert impressions here.

It sounds to me like you ought to do a mini-review for FVM. Please do post here first though.

Thanks for opening up this conversation Peter, and Tom your advice and knowledge as always is much appreciated.

Dare I ask why you don't recommend an external ND filter on a short focal length lens (or will it be way above me?)

[Peter Copestake]

Thanks again, Tom, for this explanation which I can, just, understand if I concentrate!
I your initial post on this subject you mentioned three ¼'' CMOS chips, hybrid OIS
I had to look up OIS but am not sure why it is not a good thing. Perhaps there's too much digital and not enough mechanical component to it?
And are CMOS chips not as good as good as whatever else is available these days? All I can remember hearing is their irritating habit of putting a vertical streak of light above and below a point of light.
You've probably covered all this before in articles in FVM that I haven't properly taken in but if you have time ...
I like the idea of posting here before writing it up for FVM, Tim - might, no, would, save embarrassment!
Peter.

[tom hardwick]

OK, some explanations. And just to note that I've covered all this in Positive Image (said with a smile).

Tim, this is not above you. Watch any so-so home video and when the camera's turned into the light all sorts of out of focus blotches and flares dot the image. Why does this happen, when in days gone by you could shoot with your SLR and its 50mm lens (say) and not have any of these nasty degrading spots and blodges ruining your image? The answer is basically dust and dirt on the front element, but this affects camcorders far more than SLRs. Why? Read on.

It's all down to chip sizes and focal lengths. Your SLR will use a lens of 50mm focal length, feeding a huge 'chip', to give a field of view that looks 'normal'. To get the same 'normality' with a typical domestic camcorder you'll be using a focal length of about 5mm, and the smaller the chips, the shorter this focal length will be.

Now you know that the shorter the focal length, the deeper the depth of field (dof) for any given shooting aperture. So the 50mm lens might be in focus from 2 feet to 5 feet (say) whereas the 5mm lens will be sharp from 8 inches to infinity in the same lighting conditions and using the same aperture.

If there's any dust on the front element (and in real life there always is) then on the SLR this is going to be hopelessly out of focus - and therefore invisible. But the same dust on the camcorder's lens is getting much more obvious, simply because the dof extends so close to the front element. It's the light being scattered by this crud on the front element that causes all those blotches up on the TV screen. I see it time and time again.

Now people think they want to 'protect the front element' by fitting a UV filter, or they want to add ND or a polarisor. Fine, but now you're introducing two more unclean glass surfaces into the equation, making a total of three. Not only that, but your filter is even more in focus than the front element, just because it's further forward and closer to the dof.

OK, what's to be done about it? First thing is to use a lens hood to mechanically shield the front element from any point light source (generally the sun). Second thing is to keep your front element as spotlessly clean as is possible, and thirdly is the instruction not to use any sort of filter unless it's absolutely necessary. And when have I thought it absolutely necessary? Never. The multi-coating on modern lenses is really tough, and you can clean it weekly with no fears for its safety.

I've not used filters for years, and my camcorder uses 'big' 1/3" chips. I can add colour and ND grads in post. Many camcorders use tiny 1/6" and even 1/8th inch chips, meaning their zooms start out at a 1.5mm focal length. Space your finger tips 1.5mm apart and marvel, and imagine what the dof must be like when you shoot using such focal lengths. Correct: for close up shots the dof extends within the zoom lens itself, and all imperfections are rendered sharply.

I had two matched VX2000 Sony camcorders. I set them up adjacent to one another, looking at the same scene. I fed their outputs into the same TV so that I could switch between the two cameras instantaneously. The only difference between the camcorders was that one was fitted with a 'protective' UV filter. I allowed sunlight to fall on both front elements.

Result? I unscrewed the UV immediately and skimmed it out across the lake, and I never looked back. Never. Until I did this test I had not realised how much filters degrade images from small-chipped cameras.

OK, Peter.

CMOS chips are now pretty much universal. They suit the manufacturers because they're less power-hungry and they work better in low light than CCDs. CCDs exhibit the vertical smear from point light sources, but CMOS have disadvantages too, in so far as they impart jelly-wobble to moving footage and the chip's readout means the flash banding is very common. In my view both these failings are very objectionable.

OIS is a good thing, and I'm not sure why you thought otherwise. Hybrid OIS is Panasonic's terminology for an extension in the allowable movement path of the internal vibrating elements that compensate for camera shake. It's switchable for the simple reason that it's so effective it can stabilise intended camera movement, and overshoot when said movement comes to a stop.

More questions? Fire away.

tom.

[Peter Copestake]

Thanks again, Tom. It was just your inclusion of Hybrid OIS in the list of what I thought you were saying were the unpro = consumer features that amde me think the hybrid addition was not up to pro standard, but you've cleared that up fine.
Now to wait and see.
Peter.

[TimStannard]

Thanks for the explanation, Tom. The only excuses I can offer for not having understood it from Positive Image are (a) I've been receiving FVM for less than two years, (b) the fact that I seem to struggle to remember much these days, and (c) I've been receiving FVM for less than two years.

In all seriousness, one doesn't always take in the full implication of what one reads if it's not at the forefront of one's mind at the time.

[Peter Copestake]

Hello, again.
I have now had the opportunity to handle this camcorder but not use it. At Pro-video-kit's open day at Shipley, W.Yorks, there were a number of pros interested in the same machine and I felt I couldn't demand more attention (see below).
It feels solid and the LCD panel was bright and so sharp I thought it was some smart demo picture in it, but, no, it was pointing at another Panny on a tripod a few feet away. There was a south-facing window behind me but not sunny. Still, it looked good. The screen is used for some menu features but looked very clear and actually easier to use than buttons and knurled knobs.

The zoom ring was so smooth you could certainly use it on the trot, I think, and I did not notice the 2-3 seconds lag one reviewer has mentioned. Perhaps his example was faulty.
I suppose this means it is servo assisted but I wasn't conscious of any lag.

There is a zoom button on the front of the handle which didn't seem to work anything like as well. The chap from Holdans said it was for use when it was being held low down but a description on the specs accessed through their web site (which is much fuller than any I have found going through Panasonic's own site) says it is for changing zoom speeds, so possibly not the same as on my Sony PD 170.

If I were going to replace the 170 I'd definitely be looking at this camera again but I won't because-
*Its price has risen from a 'probable' £1100 to more than £1400 + VAT
*That doesn't include a 'proper' microphone tho' the kit for attaching one is, and the mic. suggested costs £380 + VAT (The good one I have on the PD170 would probably work but that model doesn't have any built-in mic. so couldn't be used as a second camera without one.
*I cannot, without add-ons, edit AVCHD
*I cannot afford to edit HD so would be using SD so why change?

To most of you this review will be pretty useless and not worth reproducing in FVM but I thought I would add what I could.

Peter.

[Peter Copestake]

Sorry about this!
In fairness to ProVideoKit I have just noticed on their price list that tho' the list price is £1423+ VAT
they say "Our Price £1165 + VAT"
Peter