How could I know at which f-stop The HDR-A1 is shooting? - Page 4 at DVinfo.net

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Sony HVR-A1 and HDR-HC Series
Sony's latest single-CMOS additions to their HDV camcorder line.


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Old February 20th, 2006, 05:28 PM   #46
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Quote:
Originally Posted by Vincent Sanchis
I bought the camera based on the information provided by Sony and some 'independent' rewiews on Internet (I could not do it in a different way, because in my area there are not too many stores where you can purchase the 'pro' models).
I can't image buying ANY camera without trying it out first! Every Best Buy has had the HC1 for months. If you would have tried one out you would have found the lack of indication.

I also can't image buying a camcorder without going on-line.

But, the bottom line is that there is no block to your using the camcorder and although I think this is a great discussion because of all the technical information -- the "Sony didn't tell me" whine is getting old.
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Old February 20th, 2006, 05:58 PM   #47
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Quote:
Originally Posted by Evan Donn
Yes - this is one of the odd interface things on this camera which seemed to lead to the erroneous conclusion early on that you could not control/lock both shutter and iris independently & simultaneously (which apparently is the case with the earlier JVC HDV camera).
Its the JVC I was thinking about so this is good news indeed.

Control is really simple with your chart:

F2.4 0dB -- only for minimum DOF

F3.4 0dB

F4 0dB
F4 0dB
F4 0dB
F4 0dB

F5.6 0dB

Simply draw a bar underneath all the F4 settings and a dot at F2.4. And then another bar under:

F1.8 12dB
F1.8 6dB

The latter indicates settings with added gain but not too much added noise.
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Old February 21st, 2006, 03:03 AM   #48
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About HC1 aperture...

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Old February 21st, 2006, 04:46 AM   #49
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I can not imagine expressing my thoughts better than Bill McMullen has done. I agree with him in every opinion he has given.
The f-stops are standards in the 'pro' wordl, and the Z1 is not the answer to my needs, because I bought the A1 mainly for it's small size which allows me to put the camera in my suitcase together with my laptop and shooting while I'm travelling attending meetings all around Europe.

Some of you had suggested to contact Sony. I've already done it.
And the good thing is that under the European Union 'Consumer Protection Laws' one could sue them (for unfair advertising), and despite they should have the best lawyers in Europe I think there are chances to beat them in court. But of course I'm not going to do it, I have to recognise I have over-reacted about this matter.


What I can not understand is why some of you are so passionately defending Sony's position? If you do not complain, Sony will never see the need to improve their products or make their advertisement more 'transparent'. But in a free market that's precisely our strenght as customers: fight to get the most for our money.


And last but not least, and this is one of few points I agree with Steve (aside of technical advice), the "Sony didn't tell me" whine is getting old.

Let's talk on how can we can get the most from what we actually have.

PD: Take a look to the link posted by Rodolphe, I found it very interesting.
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Old February 21st, 2006, 07:32 AM   #50
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''What I can not understand is why some of you are so passionately defending Sony's position?''

Because unlike all the other camcorder manufacturers they appear to have a defined link between design, sales and marketing. If you want apertures shown on your Canon you have just three models to choose from (and I'm assuming the XL2 is still in production). Panasonic? Just two models Think the XLR equipped DVC30 is included? Nope.

Sony sell the VX2100, PD170, FX1 and Z1, and all of them pull no punches. If Sony are to be smacked for 'with-holding info from the public' then Canon and Panasonic better go into hiding.

tom.
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Old February 21st, 2006, 02:33 PM   #51
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Quote:
Originally Posted by Vincent Sanchis
PD: Take a look to the link posted by Rodolphe, I found it very interesting.
My french is a little rusty, but it illustrates very well what I was able to see using a flashlight - 4 blade diamond shaped iris with 2 NDs at various positions in the f4 range. I attempted to photograph it this weekend but there are so many reflections from the flashlight in the various lens elements that it's difficult to get a shot which shows the NDs - their method is certainly much more effective.

It also explains something I'd noticed occasionally in a few shots, especially one long focal length shot of a bird with water behind it - the bokeh has a noticeable geometric texture to it when there are a lot of out-of-focus highlights.
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Old December 15th, 2006, 06:23 AM   #52
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Quote:
Originally Posted by Evan Donn
My french is a little rusty, but it illustrates very well what I was able to see using a flashlight - 4 blade diamond shaped iris with 2 NDs at various positions in the f4 range. I attempted to photograph it this weekend but there are so many reflections from the flashlight in the various lens elements that it's difficult to get a shot which shows the NDs - their method is certainly much more effective.

It also explains something I'd noticed occasionally in a few shots, especially one long focal length shot of a bird with water behind it - the bokeh has a noticeable geometric texture to it when there are a lot of out-of-focus highlights.
Sony's US patent no. 6,533,473 describes a diamond-shaped iris with two ND filters. Figures 3 and 6 in the patent illustrate the progression as it stops down. Is this what you were seeing?

http://www.google.com/patents?vid=US...BAJ&dq=6533473
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Old December 15th, 2006, 07:51 AM   #53
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Good Work, Mike.

Are you a patent attorney : )
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Old December 15th, 2006, 08:23 AM   #54
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No, but for both the Sony camcorders and the Canon HV10 (thread titled 'HV10 - ND Gradation feature'), the patent descriptions provide more detail than is available elsewhere.

Sony and Canon have pursued different physical implementations of the iris / ND filter assembly. But the design rationale is similar -- apparently the iris can't be stopped down beyond f8 without causing diffraction problems on the sensor chip. So steps of ND filtration are added to provide the effective aperture control range that otherwise would be obtained simply by stopping down the iris to f16, without using internal ND filters.
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Old December 15th, 2006, 09:25 AM   #55
 
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Excellent find, Mike. I hadn't seen that document; it provides very useful information. It's an oldie, but a goodie!
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Old December 15th, 2006, 10:24 AM   #56
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Using the Google link below, you can search for terms in the text of patents -- something that isn't possible on the US Patent Office site.

Search terms such as "ND filter," "ND filter Sony" and "ND filter Canon" turn up many interesting results, both old and new, which give insight into the manufacturers' thinking, and quite a few specifics of the physical mechanisms and control schemes.

http://www.google.com/patents
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Old December 15th, 2006, 02:30 PM   #57
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Evan - I think you're seeing a two bladed iris inside the Sony - the top blade is an upside-down V and the bottom blade is a rightway-up V. This is much simpler and cheaper to produce than the nice 6 bladed iris as used on the VX, FX etc, but it does the job, albeit with less attractive highlights and flare when used into the light. Out of focus highlights are noticeably less attractive too.

The internal ND filtration of the PDX10, the HC1 etc is designed to stop the cameras working at any stop smaller than f/4, regardless of the focal length. Of course if it gets brighter than even the internal ND can soak, then smaller apertures are used - but this is seen as an emergency getUhome, as diffraction with 1"/3 chips becomes quite noticeable at f/5.6 and smaller - and especially so at the wide-angle end of the zoom.

Cameras with this undocumented internal ND often 'make up something the punter will believe' when 'display' is hit on tape replay. Panasonic are also guilty of this, displaying silly f/22 readouts on many of their cameras.

tom.
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Old January 9th, 2010, 06:17 AM   #58
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How does the internal ND filters work with external one

Hello again after some years,

I am using a HVR-A1 and would like to know, if anybody knows how the three (?) internal ND filkters work togehter with external ones. Has anybody used them in combination?

In addition, am I correct with the following assumption regarding the exposure steps of the A1?

f4: 0db/None ND
f4: 0db/ND2
f4: 0db/ND4
f4: 0db/ND8

Thanks,
Peter

Last edited by Peter Muller; January 9th, 2010 at 11:36 AM.
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Old January 9th, 2010, 08:38 AM   #59
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I'm not sure if the A1 has separate ND filters - I would expect it to have a varying density filter so that the more it moves into the light path the more light is absorbed. I don't know though _ I haven't looked down into its lens.

So what happens is this. You're filming at f/2 (say) and it gets brighter. The iris closes to f/4. It gets brighter still and now the ND absorbs the light. If it gets brighter than a theoretical f/11 (with max ND in place) the iris will start to close again, or in some cases the shutter speed will shorten.

It's far better to do this yourself (film at 1/100th rather than the default 1/50th) if it's very bright and avoid the use of external ND filters altogether. They cause flare spots with such short focal lengths and reduce the hood's efficiency. Not good.

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Old January 10th, 2010, 01:29 PM   #60
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Thanks a lot Thom for you explanation and advice!

Another question is what will happen when the varying density filter work together with an IR filter or circular Pol filter I am also considering to use.
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