AG-AC90 Review - in the Dominican Republic

http://www.definitionmagazine.com/j...mcorder.html?lastPage=true&postSubmitted=true




NOA said:
Barry, Not questioning your findings but on hdmagazine they state the camera has very poor resolution which I find very hard to believe after seeing some samples on Vimeo, and that's after a compression. I wonder if he was filming in DV mode :)

But they also claim there is quite a delay between turning the rings on the lens and the actual adjustments and that this is in particular for the zoom ring which would take seconds before something happens? Did you experience a significant delay between turning the rings and the actual changing of zoom, iris of focus?
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Yeah, that makes zero sense. Unless he was running around shooting at f/11, in which case yes, diffraction would cause low-resolution images. But at f/2.8, this thing is sharp sharp sharp sharp.
 
Hi Barry

How would he be able to close the iris down to F11??? I was under the impression that even in full manual, if you close the iris setting the auto ND filters will still progressively move out of the path so even manually F11 is actually F2.8 + ,say, 1/64th ND?????
What do the auto ND's do in full manual??? On the MHC 40/80 they definately look like they stay in cos I can switch from auto iris to manual and the exposure stays the same until I manually adjust it unless the shutter speed is providing compensation??

Chris
 
ChrisHarding said:
Hi Barry

How would he be able to close the iris down to F11??? I was under the impression that even in full manual, if you close the iris setting the auto ND filters will still progressively move out of the path so even manually F11 is actually F2.8 + ,say, 1/64th ND?????
What do the auto ND's do in full manual??? On the MHC 40/80 they definately look like they stay in cos I can switch from auto iris to manual and the exposure stays the same until I manually adjust it unless the shutter speed is providing compensation??

Chris
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The ND's are not infinite, after a few stops, the iris continues to close, all the way to "shut."
 
I'm reading this thread with great interest as I'm more and more convinced I should buy 2 AC90 units to replace my ageing Sony Z1/FX1 cameras!. My budget however can stretch a little further - would I be better looking at the AC130 or AC160 - what would be the benefit on spending the extra on either of these cameras?

I should say I'm a solo wedding videographer and am always flitting between manual and auto depending on the pace of the day so a fast and accurate auto setting is a must, as well as being able to switch to manual with ease.

Thanks

Pete
 
Thanks Chris - I thought I'd seen somewhere about poor auto exposure/focus in the 130 - you've helped a lot there! I'm hoping to get my hands on an AC90 later today for an hour - I hope it's everything it's cracked up to be!
 
ChrisHarding said:
I was under the impression that even in full manual, if you close the iris setting the auto ND filters will still progressively move out of the path so even manually F11 is actually F2.8 + ,say, 1/64th ND?????
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No, the ND filter isn't that strong. It only comes into play between f/2.8 and f/6.4. In that iris range, it's all f/2.8 + ND. But once you go past f/6.4 the iris is physically closing down again.

What do the auto ND's do in full manual???
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One question mark is sufficient! :)

The misunderstanding here is that the ND is somehow "auto". It isn't automatically selected, it is ALWAYS integrated into the iris, no matter how that iris is selected. If you choose the range from f/1.5 to f/2.8, there will never ever be any ND filter in place. If you choose any iris from f/3.0 to f/11. there will always be ND filter in place. It starts moving in at f/3.0, and it continues moving more and more in until it's fully engaged at f/6.4. From then on out, the entire full strength of the ND will always be in place.
 
As for the "low resolution" comments from that other guy -- another way he could have gotten those results would be if he was shooting at full telephoto with the i.Zoom feature on. That's a digital zoom, and at full zoom it'd render an image that would be comparatively low resolution because it would have been with a 2x digital zoom effect! So definitely turn i.Zoom off if you're looking for sharp imagery.
 
Thanks for the explanation Barry

The multiple questions marks are a habit not trying to emphasise a point at all. I must really stop doing that. Your helpfullness is always appreciated

Chris
 
As is your enthusiasm and willingness to share and help other members on the forum. That's what makes this place great, is members like you who try to assist other members!
 
Please what battery type should I but for the AC-90? is it the CGA-D54? The dealer I am hoping to buy from is trying to sell me a generic battery for £184!
 
Hi Peter

Yeah right! A generic D54 off eBay should cost you little more than $30 !!! I use a couple of generics as backup but Panasonic OEM batteries for important stuff. The generics work fine but tend to fade after a year. If you are doing weddings then use genuine batteries on stuff like the ceremony, speeches and events that cannot be done over!! I often clip in a generic if I'm filming general dancing ..if the battery fails it's no big deal at all. At GBP154 you should at least be getting a gebuine Panny battery. As a guideline the genuine D54 Panasonic from Global Media Pro is listed at AUS$108.00 which is around GBP60 I think so the 154 is way off target!! GMP also do a very nice generic that lasts well!

Chris
 
I'm with Chris,
My experience with generic batteries since way back in the vhs days, through hi 8 then digital then HD has always been a
disappointment. Buy only OEM. It seems expensive but they invariably out perform generic/ fake stuff. Generic battery record duration is in my experience always shorter and as Chris says, they fade very quickly and terminally! I have repeated incidents of 12 months or so for generic against 3-4 years for OEM. Do the math- no brainer for me.
Cheers!
Rod
 
HD Magazine just posted a response to their evaluation that the AC-90 is soft :



"We test the MTF of all the cameras we review, to determine the 'sharpness' of the image.

The small pixel pitch (about 2.5 um) corresponds to diffraction limited resolution of red light at around f/2.8, which probably explains the poor MTF results at apertures smaller than this.

December 11, 2012 | Adam"



Barry_Green said:
I don't know what hdmagazine is, I haven't seen that, but I can tell you from pointing an AC90 at a resolution chart that it is extremely high resolution. Extremely.


Iris and focus are instantaneous. On the early, early, first preproduction model, the zoom ring was atrocious. It was so disconnected from reality that it was, in my opinion, unusable. They fixed that, and the zoom ring is quite usable now. However, it does respond differently (which is a good thing). On the zoom rocker it responds immediately to any input, which means that when you press the rocker it starts zooming instantly, and stops zooming instantly. On the zoom ring, it's "feathered" -- as you first move the ring, it zooms slowly for a tiny fraction of a second, ramping or feathering into the zoom. And when you stop, it takes a fraction of a second to feather down to a stop. That helps avoid the jerky start/stop syndrome. It is not a zoom ring like on the prior Panasonics. On the prior Panasonics the zoom ring was a direct manual physical zoom, so you had precise control, but it was difficult to feather into and out of a zoom. On the AC90 you can have both -- feathered in/out by using the ring, or direct control through the rocker.

Even so, I find the zoom ring (while vastly improved) is not on par with their more expensive cameras. If you really crank the zoom ring around (like trying to do a minimum-to-maximum snap zoom) you'll see the zoom action speed up and slow down in noticeable increments. So the zoom ring is there, and it does work, and it does serve a purpose, but frankly I find myself using the rocker much more than the zoom ring.
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Hi Lou

I'm not sure if the 90 has the same system as the 40/80 but in full auto (or just auto iris) you are seldom at anything like F11. My 82's auto change the iris/ND combo AND the shutter so on a bright day my shutter will be up a 1/2000th which probably allows the iris to be lower. Barry mentions that the ND/shutter combo work up to F6.8 if I'm not mistaken so really the only time you might get a res drop would be in bright sunlight so there is certainly nothing wrong with popping on an ND if you are shooting in bright sun.

I think it was also Barry who suggested restricting the iris on the bigger sensor 130/160 to an absolute minimum of F8 (any smaller and you will lose res) and suggested sweet spot seemed to be F5.6 - Maybe they tested it in bright lighting in full manual and locked the shutter at 1/50th which closed the iris. The solution in bright light and full auto is a simple ND filter and Barry has already suggested this to AC-90 users. Put the big brother AC-160 into manual, turn the ND filters to OFF and see who the image degrades and that is with 1/3rd chips not 1/4.7 ones. I wonder if these guys make a note of shutter/iris settings when testing "sharpness" ?

Chris
 
The small pixel pitch (about 2.5 um) corresponds to diffraction limited resolution of red light at around f/2.8, which probably explains the poor MTF results at apertures smaller than this.
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I have no idea what he is saying.
 
Peter Rush said:
Please what battery type should I but for the AC-90? is it the CGA-D54? The dealer I am hoping to buy from is trying to sell me a generic battery for £184!
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In the states I was able to buy 3 of the lhttp://www.bhphotovideo.com/c/produ...GR_D28_CGR_D28_Lithium_Ion_Battery_7_4V_.html for around $30 each with shipping. Pearsont is heavily used by B&H so should be reliable. However, of the 3 batteries only 1 worked. I am returning the other 2. Notably all three batteries (despite being in the same packaging and labelling) have cosmetic differences. Oddly the 2 I am returning both have a little switch you can toggle I guess to indicate fully charged . I am hearing the same comments from others about "off brand" batteries (which makes sense somewhat), but even OEM batteries are generally repackaged from somewhere else.
 
Lou Bruno said:
"We test the MTF of all the cameras we review, to determine the 'sharpness' of the image.

The small pixel pitch (about 2.5 um) corresponds to diffraction limited resolution of red light at around f/2.8, which probably explains the poor MTF results at apertures smaller than this.
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Well, yeah ... that's what I said. Stop it down really far and it'll get really soft, so -- as the doctor told the patient -- don't do that. This camera is extremely sharp when used properly. Sharper than cameras that cost 3x as much. It is a very, very sharp camcorder.

That iris limitation is exactly why they designed the integrated ND filter the way they did, to keep the iris in the sweet spot as long as possible. F/6.4 is the deepest you can go in the f-stop range and still have 100% sharpness. And I find f/8 to be acceptable. But don't go beyond that, period.
 
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