How could I know at which f-stop The HDR-A1 is shooting? - Page 3 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 16th, 2006, 07:41 PM   #31
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Quote:
Originally Posted by Steve Mullen
If you lock ONLY the shutter-speed -- do the ND filters continue to work?
Of course. Based on the data code from some full auto stuff I've shot the camera basically does it's best to keep things at f.4 whenever possible and primarily achieves this via the NDs and shutter speed(if you don't lock it).

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Of these 7 positions -- how many are GAIN UP positions?

And what GAIN values do they represent?
I'll have to shoot a test and check the data code to confirm, but based on the chart I linked above the values should be 18db, 15db, 12db, 9db, 6db, 3db, and 0db - all at f1.8.
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Old February 16th, 2006, 08:01 PM   #32
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Quote:
Originally Posted by Evan Donn
I'll have to shoot a test and check the data code to confirm, but based on the chart I linked above the values should be 18db, 15db, 12db, 9db, 6db, 3db, and 0db - all at f1.8.
Yes that'll be it. Then going further left leaves gain at 0db and opens up aperture half-a-stop each stop (i think). (From my testing on a different Sony cam admittedly but am pretty sure it's same on HC1).

One question i have is: can someone confirm that 6db of gain is equivalent to 1 stop ?
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Old February 17th, 2006, 02:16 AM   #33
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Stu, the moving (and undocumented) ND filters are very obvious on the PDX10 and I've written about it in my various test reports, so I assume they'll be just as clearly visible on the A1/HC1.

What actually happens is that if you're filming at full telephoto in the manual exposure mode the camera will open to full aperture of f/2.8 (f/2.1 in the A1's case) If it gets brighter - or you want to film at a smaller aperture - you can film at f/4. If it gets brighter still the camera has no more apertures up its sleeve - it now resorts to using the first of the three ND filters. If it gets brighter still the second and then the third ND come into the optical path.

The PDX10 has three ND filters, all of them automatic in operation, all of them uncoated gelatin filters that bob in and out of the light path depending on ambient lighting conditions. It works well, and their position in the element line-up means they're way out of focus. This is necessary as you're often filming through the 'edge' of the filter. Not nice, but invisible.

Turning the exposure wheel (actually an ND wheel for most of its life) puts unacceptable half-stop visible jumps into the footage. This is a crazy state of affairs that seems to have been carried over into the A1.

Evan, if the diaphragm in your A1 is anything like the iris in the PDX10, then you'll find it's not four bladed but two. After the 'perfect circle' six bladed diaphragm of the PD100, this looks like penny pinching, and Herr Zeiss would not be best pleased. And you're right - f/4 is the 'perfect' aperture for a 1/3" chipped camcorder. Well away from both vignetting and diffraction.

Stu - you're quite correct. 6 dB of gain is the equivalent of one stop.

tom.
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Old February 17th, 2006, 11:07 AM   #34
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Quote:
Originally Posted by Tom Hardwick
This is necessary as you're often filming through the 'edge' of the filter. Not nice, but invisible.
This appears to be what's happening on the HC1/A1, although I could only see 2 distinct filters which stop at 3 positions across the aperture.


Quote:
Evan, if the diaphragm in your A1 is anything like the iris in the PDX10, then you'll find it's not four bladed but two. After the 'perfect circle' six bladed diaphragm of the PD100, this looks like penny pinching, and Herr Zeiss would not be best pleased.
I could see four blades which appear to each move independently, producing a diamond-shaped opening which is wider than it is tall. I'm going to try and photograph the aperture & NDs and I'll post a link once they're up.
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Old February 19th, 2006, 04:15 AM   #35
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Why I Need To Know The F-stop?

I've read a lot of interesting comments on this thread, but I think we have missed the main point and the reason why I started this thread, which was the capabilities of the A1 to shoot a dramatic short or feature film.
Some people asked me why I need to know at which f-stop I'm shooting.
To answer the question we just have to go to the basics of filmmaking.
Let's take a dramatic scene of 'shot and reaction-shot' betwen two actors (if you don't understand what I mean, see the PostData below). In this kind of shots you have some basics: one of the most important is that you have to shoot both shots with the same f-stop (usually 5.6 f-stop in a standard camera). That's what I learned in the Film School.
So the point is how do you know you are following this rule, which I think is one of the most basic rules of filmmaking, without any feed-back from your camera (The A1 in this case).
This is point I wanted to clarify. This thread has become very interesting (and I would like to thank you for all the comments), but we have moved the target from the basics of filmmaking to a sort of 'A1 engineering forum', and in the in end I have learned some 'tricks' to fix something which should be fixed by Sony simply updating the firmware to let you know at which f-stop you are shooting.
To sum up, Sony has made a great marketing mistake not giving this information to the user of a camera sold as 'pro' model. By the way, Sony's marketing is not perfect (in my humble opinion is quite bad), they have made a lot of marketing mistakes (despite they use to have the leading technology), and that's the reason why Panasonic or JVC are still alive and quicking: because they have more 'fair-play' with their customers. I hope the new chairman (which for the first time is not japanese) is going to improve their marketing way (notice that Sony has made most of their profits with the PlayStation, not with video cameras).

If I had the chance to return my A1, I will do it, and I look for something really 'pro', something without stupid 'compromises' hidden by the seller and the producer. Unfortunately I can't, and I will have to buy another camera to shoot my 'indie shorts'.

PD: As you have noticed english is not my mother tongue, and sometimes I can't find the right words to explain what I want to say.
Regarding this post, I'm not sure about the expresion 'shot and reaction-shot', but what I mean is the situation of two actors in a conversation, while the camera is shooting at each one of them, from a diffent position of the camera.
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Old February 19th, 2006, 08:43 AM   #36
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If you had a two A1 camera shoot on the same subject Vincent they could both be set the same by having their exposures locked down whilst sitting side by side looking at the same subject. You wouldn't know what this aperture was, but then you could hardly blame Sony for this as you bought the cameras knowing this situation existed. Sony hid nothing from you.

On the A1, here's what happens when you record a few seconds at each "stop" setting of the exposure control:

F1.8 18dB
F1.8 12dB
F1.8 6dB
F1.8 0dB
F2.4 0dB
F3.4 0dB
F4 0dB
F4 0dB
F4 0dB
F4 0dB
F5.6 0dB
F8 0dB

So, clearly the neutral comes in at F4 (and does 3 stops-worth), and when that runs out, it carries on with the iris. That's certainly what I see when I peer into the lens with a little Maglite. For this run, the shutter was fixed at 1/50.

So you think Sony's marketing is quite bad? I think otherwise, as I've seen them introduce formats (Hi-8, Micro MV, DVD, HDV etc) and then go on to sub-divide the niche they've created. If Sony don't make the camera you're after then my guess is it's not being manufactured.

Many of Sony's cameras have kept you in the dark over what aperture is being used when you shoot. The TR2000, TRV950, PDX10, HC1000, HC1 and now the A1. It's nothing new, Sony have always offered cameras with full readouts: VX1000 and 2000, TRV900, PD100, PD170, FX1, Z1 and so on. Everyone's catered for.

Sales, design and marketing are an unlikely mix of people. The marketing
muscle promotes Sony (say) as the best quality camcorders in the world. The sales people want the maximum amount of gizmos included with every camera because it ups the perceived value for money. The design department want to make the best camera they can at a particular sales point.

So Design says that if the camera's going to sell for £500 it can have a very sharp 10x zoom or a so-so 20x zoom.

The Marketing people want to go with the 10x zoom - that way the magazine
tests say how good Sony lenses are.

Sales want to go with the 20x zoom. They know Mr Punter will have the 20x
zoom Canon on the store counter along with the 10x zoom Sony, and Mr
Punter will walk with the Canon.

So Sales say: make the camcorder take very good stills then. Design say:
but that will make it less good in low light. Sales say: put a flash gun on
it then. Marketing say: That will spoil the sales of our still cameras, so
reduce the camcorder's stills quality.

Sales agree. Add sepia, fades, zoom trails and fancy menus. Design points
out that this will raise the cost, and Marketing strikes a middle ground, while admitting that such useless add-ons help move the metal.

So camcorders - ALL camcorders, are compromises. The VX2100 has a 12x zoom whereas the Canon GL2 has a 20x zoom. Sony is superb in low light, the Canon is cheaper. VX takes so-so stills, the Canon is better. And so on.

Which is why people should avoid mega-pixel camcorders - they're trying to
be jack of all trades, yet are master of none. Camcorders with 25x zooms
that cost £350 will struggle in average light, let alone poor light. Their
colour balance circuits will be mediocre, their microphones will be awful
and they won't take much punishment.

There's no such thing as a free lunch. Remember Sales knows best: huge long specifications which include useless offerings are great on the sales counter.

tom.
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Old February 19th, 2006, 10:56 AM   #37
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I made a little f-stop table, printed it on a sticker and stuck it under the exposure bar. It can be a bit tough to read because its so small but it does help. The link below is the vectorized file.

http://www.ocf.berkeley.edu/~mdlee/fstopmeter.eps
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Old February 19th, 2006, 11:57 AM   #38
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Wow Min, very neat.

Do you think you could post a picture of how you attached it to your camera?
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Old February 19th, 2006, 02:31 PM   #39
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Quote:
Originally Posted by Vincent Sanchis
So the point is how do you know you are following this rule, which I think is one of the most basic rules of filmmaking, without any feed-back from your camera (The A1 in this case).
You do so by learning how to use your specific camera to achieve the particular look you want or need. This is something you need to do whether the camera tells you it's f-stop or not.

Using the same f-stop when doing a shot/reverse shot is not a bad idea, and it's a very easy thing to achieve with this camera. Lock the exposure, shoot one angle, then shoot the other without changing the exposure setting. Both shots will have the same aperture setting and therefore the same picture characteristics (especially if you also keep the zoom setting consistent). This doesn't require you to know what f-stop you are using - you use the one which gives you the depth of field you want when looking at the monitor. All you need to know is that the f-stop doesn't change if the exposure setting doesn't change.

Trying to always use f5.6 when doing a shot/reverse shot because that's what you were told in film school is a terrible idea. Why f5.6? f5.6 is going to produce very different looks depending on the camera and lens combination. If f5.6 is indeed a standard convention in hollywood films it's most likely referring to a 35mm film camera and will produce a look which is much different than your A1 will produce. You just need to figure out where to set the exposure bar on your camera to achieve the look you want.

All of the technical stuff we've ended up discussing in this thread will enable you to determine the best settings for your A1 when you are shooting your dramatic short or feature film. Without an understanding of the technology behind the camera you will be stuck following guidelines like the "f5.6 for shot/reverse shot" which are essentially meaningless. The A1 provides sufficient control over the image to produce pretty much any look or type of video you wish to shoot - but it's your understanding of how to use the camera which will result in great video, not features like an f-stop readout.

And the lack of an f-stop readout is not a marketing mistake - there is simply no real competition at this point for the HC1/A1. If an f-stop readout is an absolute necessity for you, then you spend a little more and get an FX/Z1. Sony knows this will be the case for a lot of people and will push them to the more expensive version - so it's not a marketing mistake but a good marketing move. Until someone else can come up with some competition in the same price range that's the way it'll be.
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Old February 19th, 2006, 10:06 PM   #40
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Quote:
Originally Posted by Evan Donn
Lock the exposure, shoot one angle, then shoot the other without changing the exposure setting. Both shots will have the same aperture setting and therefore the same picture characteristics (especially if you also keep the zoom setting consistent). This doesn't require you to know what f-stop you are using -- you use the one which gives you the depth of field you want when looking at the monitor. All you need to know is that the f-stop doesn't change if the exposure setting doesn't change.
You've expressed very well WHY I asked him the question of WHY he needed to know the F-stop. And, let's add more to your answer.

The reality is that there is no DOF control with a 1/3" imager camera except by shooting at 1.8 or 2.4. This, of course, is not the setting he'll want for optimum image quality. So the concept of 5.6 must be discarded immediately if he wants minimum DOF! Worse, he'd have to shoot at near full Tele which may, in a small room, make his arranging the shot difficult because of minimum focus distance at Tele.

I'm convinced there are a huge number of folks who learn a way of doing things on one of type of equipment and don't understand the rules change with a different type of equipment. Fundamentally he needs only make a series of 4 marks on the LCD that are these openings:

1) F2.4 0dB -- only for minimum DOF

2) F3.4 0dB

3) F4 0dB
F4 0dB
F4 0dB
F4 0dB

4) F5.6 0dB

Clearly, as long as he keeps exposure wihin (3) -- which he must do by lighting -- he's fine.

Question -- with an AE driven system he must also keep shutter-speed constant, which he does by SETTING it at 1/60th. Once it is SET, when he adjusts Exposure I assume ONLY the Iris is being controlled -- correct?

But now when you LOCK exposure -- is it certain the Shutter-speed remains as it was as well as well as the Iris remaining as it was? Right now I can't remember if you have to switch the Shutter-speed to AUTO *before* LOCKing the exposure.
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Old February 20th, 2006, 02:44 AM   #41
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Quote:
Originally Posted by Steve Mullen
Question -- with an AE driven system he must also keep shutter-speed constant, which he does by SETTING it at 1/60th. Once it is SET, when he adjusts Exposure I assume ONLY the Iris is being controlled -- correct?

But now when you LOCK exposure -- is it certain the Shutter-speed remains as it was as well as well as the Iris remaining as it was? Right now I can't remember if you have to switch the Shutter-speed to AUTO *before* LOCKing the exposure.
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).

If you set a shutter speed and then press the exposure button, the shutter speed button becomes grayed out and you cannot change the speed further - however, the speed doesn't change from what you locked it at. The current speed will still be displayed on screen, and despite forcing extremes of both under- and overexposure I have never been able to get it to change(either as indicated or visually) once locked. Now using the exposure lever is only changing the gain (first 6 positions) or iris+NDs. If you want to change the shutter speed you have to press the exposure button (returning the exposure to auto), change the shutter speed, and then press the exposure button again to return to manual control. So you can control & lock both simultaneously, you just can't adjust them both simultaneously - which I don't consider a significant limitation because in most cases I will set the shutter speed once up front for a particular situation and then make all further exposure adjustments with the exposure control.
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Old February 20th, 2006, 03:33 AM   #42
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doing a shot/reverse shot

Thanks for all your answers.
But just a few more details:

1. Doing a shot/reverse shot at 5.6 f-stop was JUST AN EXAMPLE, that you learn as soon as you start a course in a Film School. Of course I know it varies from camera to camera, and even for different dramactic situations.

2. The question above mentioned by Steve is very interesting. Is there any answer to it?. I think if you lock the exposure, probably the camera will change the shutter.

3. What happens when you do your shot/reverse shot at a different time (maybe one of the actors is ill, or arrives later, and your schedule doesn“t allow you to spend your time waiting)? Maybe I will be able to fix it with the way some of you had posted. But why should I spend so many time doing this things, when every camera sold as a 'pro' model (except the A1, as far as I know) have direct access to the iris?

4. Someone said that Sony has hidden nothing. I don't agree. 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).
So, I just have the oportunity to read the information provided by Sony, and I can assure that they never mentioned the lack of iris control or information on the f-stop. The same applies to the seller. And the 'supposed' independent reviews on Internet didn“t mention it (by the time I bought the camera, the only problem found by these people was 'the bottom loading').
And I would like to clarify that I'm talking about the A1 (a 'pro' model according to Sony's information), not the HC1 or FX1 (which are sold as 'consumer cameras'). How could I imagine that a 'pro' model lacks an appropiate iris control? I could not. For the forthcoming Sony's products I bought I will be more cautious...if I bought something made by Sony again (I doubt it).

My advice for serious filmmakers (aside those who shot docucumentaries) is to look for a different model (or brand) with less 'copromises' which I consider essenttials. If you don't believe me try reading 'cinematography.com' forums or others similar to this, and you'll realize what the cinematographers think about the A1: just the same as myself.
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Old February 20th, 2006, 04:19 AM   #43
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Vincent, you say: ''I think if you lock the exposure, probably the camera will change the shutter.''

This doesn't make sense. If you lock the exposure then you lock the iris, the shutter speed, the gain setting and the ND filtration. If it's locked, it's locked.

I can understand that you feel upset that Sony were 'economical with the truth' when giving you the technical specification of the A1, but I assure you the PDX10 (the model before the A1) was exactly the same - no proper aperture readouts - even in the replay mode. Sony sold bucket-loads of them. Why? Great pictures from a tiny box.

Panasonic are shy too. I have the DVX100A brochure - many glossy pages of enthusiasm for the camera and yet not once does it tell me what the maximum aperture of the lens is at full telephoto. And this for a camera! It's the same with all their cameras - especialy with the ones that use internal ND filters. They keep quiet about the compromises.

Why didn't you ask here for info before you paid for the A1? That's what the web's so good at - telling the truth behind the glossy brochure pages. Sony will continue to sell the A1 simply because today there's simply no competition for it at that price/size/weight/performance point. It produces pictures way better than any Canon, Panasonic, Sharp, JVC - even when those others cost twice the price. And for that very good reason you must accept some compromises.

Go out and enjoy your A1. Rejoice in the fact that you can shoot alongside people with much bigger and more expensive cams and KNOW that you're bring home footage that's 4x as sharp. That's quite a knockout punch.

tom.
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Old February 20th, 2006, 03:40 PM   #44
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Look, the reason this A1 camera should have the f-stops rather than 'clicks' or '+/- notches' is that we already have a set standard for lens settings - f-stops!

Why the need to translate '6 clicks from the right' to '0db' when we already have correct, consistant nomenclature for this? Terms that are actually used by the very same camera when you read the data of an existing shot on tape?

Don't defend Sony for 'not hiding anything,' it's OK as a consumer to ask for more, especially when Sony markets this as a 'pro' cam. Pros use 'f-stop' in their canon, it's a standard.

It's not our fault Sony didn't put the pro features in - telling someone they "should have looked here first to learn more about the camera before they bought it," well, that's just batting for the other team, in my eyes. I also had trouble with features missing, despite some seriously believable signposts telling me otherwise:

http://www.dvinfo.net/conf/showpost....5&postcount=13

Saying the consumer needs to be more aware and not purchse something if the features you want aren't there... That logic works well if there are a lot of choices in the market, like say, if you're looking for a 5-megapixel still camera - there are a lot of those, and you can 'punish' the manufacturer by not purchasing the camera lacking features you want. Evan Donn presented this same point very well above.

But this is a very limited market with under 5 cameras at this price point and physical size. There really is no other choice, so asking why certain things are omitted is fine with me. It's still a great value, I know - but Sony created an 85% solution when they could have answered 95% or 100%. Hopefully Sony will actually create an A1 with the pro settings of a Z1; it's still a different camera with different strengths.

Personally, I could have stretched (_quite_ a stretch for me) financially and gotten the Z1, but the real appeal of the A1 was the size - I know I'm missing the 3 CCDs, the manual buttons and knobs everywhere, but taking some of the electronic features and dumbing them down is disappointing, and I don't mind saying it - that's why you make the HC1. But the A1?

Yeah, of course I still bought it.
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Old February 20th, 2006, 04:24 PM   #45
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Quote:
Originally Posted by Bill McMullen
But this is a very limited market with under 5 cameras at this price point and physical size. There really is no other choice, so asking why certain things are omitted is fine with me. It's still a great value, I know - but Sony created an 85% solution when they could have answered 95% or 100%. Hopefully Sony will actually create an A1 with the pro settings of a Z1; it's still a different camera with different strengths.

My point isn't to defend Sony's BS marketing tactics. But just because I don't like them doesn't mean Sony is wrong to do them.

The answer to the question of why certain things are omitted is that there is no other choice. Not only is there no other choice, but at the next step up (the Z1) there isn't even much - you'd have to stretch as much or more again to go from a Z1 to a competitor's product as you would to go from an A1 to the Z1. So the choice is really between two Sony products, and I completely understand why Sony would try to skew that choice towards the more expensive camera. I don't like it, and of course I have the right to ask Sony for more, but Sony also has the right to do whatever they want with their products.

All that aside, my point for Vincent is that if you've already got the A1, you can't return it and don't want to sell it and get something else, you can still go out and shoot great videos with it. Yes it means you'll have to learn to deal with the quirks of the camera, but I have yet to work with a camera where that wasn't the case.

Contact Sony and let them know that you're unhappy with their marketing tactics and that you won't be purchasing any products from them in the future. Let them know that you aren't the only one and that this is a general concern in the community. Write up your own reviews of the camera and post them online to help others avoid the same situation you find yourself in.

But while you're doing all that take the A1 and learn how to use it to take the images you have in your head and put them onscreen - despite Sony's marketing decisions the camera is still capable of producing an amazing image - as long as you know how to use it (and can give it enough light).
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