sensable Lux
 

Is there any change in the LUX sensitivity of 953/gs100k if you use large wide angle lenses?
(like Aspheron)

if you can show a test pic would be great if there's any change.

This has been discussed before here and at dv.com's camera forum. A wide angle adaptor will not decrease the lux requirements of your miniDV cam. Here's a very lovely thread about this topic:

http://www.dvinfo.net/conf/showthrea...&threadid=9862

Thanx Frank =)

I've been looking for this certain other thread, but I think it got moved. It was even more lovely than the thread I posted above. I'll keep searching. :-))

I found it! But it's about pixel shift technology. Oops. (Funny as H_ll---now located in Area 51)

http://www.dvinfo.net/conf/showthrea...&threadid=9491

Frank... those people wrote a few books in the first thread you posted, but... no real tests =)
incredable
(why someone didn't just try it?)


oh.. hahaha... it's too late for comedy =) I'm reading the second thread (about the 3CCD cam that's not)

.. well...
little knowedge is a very dangerous thing =)

One member that posted there has a PHD in Broadcast engineering, or something like that, and Jeff teaches photography at a college or a university. Regarding a test. Yes, that's a good idea. But when I tried a couple of wides on my MX300 (in low light), I couldn't tell any difference. Perhaps you can take your PV-DV953 somewhere and shoot some test footage with a wide or 2. Are you in Toronto? Henry's probably carry the 43mm Tiffens.

Adding a wide angle conversion lens to the DV953 does not make it more sensitive. The aperture and gain settings do not decrease when I use a .42X fisheye on the 953.

=) ok
(since you've tested it and there's no difference)

Otherwise.. the theory in practice, cannot replace the practice in theory. ;-) -> or HPD in theory does not help you in practice :)

Lux is the measure of light falling onto an object. So lux only changes by the source, not the angle of the lens on the camera.

If "this" were true, wide angles for pulling in more light, every Tom, Dick and Harry would be using wide angles on their cams, including this guy; and these adaptors would be big business---but, alas, it's not the case. :-))

Rob, you should tell that to those dumb-nuts that made the Hubble telescope. if they only knew what you know! =) they could have acheaved the same result with much smaller lesnses.
;-)

.. talking.. talking.. and no one posted any test pics...

if you have large lenses to put on your cam, make a shot without them, then put it "on"
move the cam (closer) so you have the same scene visible as in the first case. make another shot
then compare.. or better yet .. post them =)

A lot of members here own a wide lens for their Pana cam, and none of these mambers have ever mentioned that they have noticed a difference, except that everything gets wider. :-))

Heh guys before you throw insults at people expecting that wide angle lenses might help for sensitivity lets look at it this way. If i were to put a 2x converter on my cam it would take light away. in a slr camera lens, if i put a 2x converter on the back of the lens it will double the fstop. this considered it would be logic that if you used wide angle converters it would do the opposite even if it might not. also you look at slr lenses again and take a wide angle lense and it might be f 1.8 or something similar to that. take the most expensive 600 mm lens and the best it will be is 2.8 so explain that. you can see the logic. also you could look at it in another way. a wide angle converter usually has larger elements so you would assume that it would let less light in. you look at it like a magnigying glass and when you put it in the sun and focus it on something to burn it. if you make the size of the light on the object the same size with two different size magnifying glasses the larger of the two would have a brighter and hotter focal point then the smaller one so the intensity would be higher indicating that a wide angle lens just might let in more light because after all the focal point will be the same all the time being the size of the ccd.

Thats my arguement so tell me why this may not be true
Justin

=)
Frank I can go into proving my point, but I saw so much written, and still there's no resolve. I don't have the option to test this, so if you do please test it.
I see that this test in particular can be a big pain... for some reason =)

I haven't paid much attention to the work done on the Hubble but you cannot increase the amount of light gathered by using smaller lenses and I did not say that. The only way to increase the light gathering is by increasing the size of the front element.

I say light gathering because you cannot increase the amount of light, or magnify it, any other way. A wide angle lens only takes the available input of light and places it on a different area of the ccd or film. That amount of light does not increase or decrease because you would be creating light with a lens which is impossible.

Light travels in a straight line. The number of "light lines" is a constant unless the scene or light source changes. It's what makes depth of field work. By stopping down a lens you are cutting off scattered "light lines" which can't be focused....man, I really am not in the mood to go into all of this. I've been up all night.

Quote: Rob
--------------------------------------
...only way to increase the light gathering is by increasing the size of the front element.
--------------------------------------


so we agree that the front element increases the light gathering.

--------------------------------------
I say light gathering because you cannot increase the amount of light, or magnify it, any other way.
--------------------------------------

if you are "gathering" more light you get more light. you are contradicting yourself here.


-------------------------------------
A wide angle lens only takes the available input of light and places it on a different area of the ccd or film.
-------------------------------------

do you mean your CCD becomes larger? haha =)
and since you "gather more light" you get more light to put (focus) on the same CCD on the same elements.

-------------------------------------
That amount of light does not increase or decrease because you would be creating light...
-------------------------------------

the focused light does increase when you have a larger gathering element...


I can see you've been up all night =) you make no sense =)

(again.. talk is cheap)

No I am not contradicting myself. You are confusing "gathering" light with "magnifying" it. Magnifying means to increase the amount while gathering means collecting what is there.

Think like this: when it's raining you can set a bucket out to collect the rain. You can set a larger bucket out to collect more rain. In neither case does the size of your bucket make more rain.

Placing light on a different part of the ccd does not make the ccd larger and I don't know how you got that idea.

When light shines on an object, a certain number of photons strike and, presumably, reflect off that object and head in various directions. If all the light at one point equaled 10 photons, just to pick a number, the angle of the lens does not change that. That is why the inverse square law does not apply to the distance to the camera, only to the placement of the light source.

All of this is simple optics and physics.

Rob... buddy... think for a second... =)

are you teling me that when you put wide angle lense your CCD gets larger? =))

Quote:
---------------------
Think like this: when it's raining you can set a bucket out to collect the rain. You can set a larger bucket out to collect more rain. In neither case does the size of your bucket make more rain.
---------------------

but in the end of the day you have the same size CCD. that means that you have to pour the "water" you gathered from the larger bucket into the smaller one. and what matter here is the depth of the water you gathered. (your CCD's area surface does not change)


--------
Placing light on a different part of the ccd does not make the ccd larger and I don't know how you got that idea.
--------

you cannot place the light on a larger area (as in the given examples by you). like in the larger bucket -> that has larger bottom surface. if you use this as anology to light and CCD, you mean that the light in second case hits larger surface (larger CCD). and this is not the case.
you get that more light has been focused on the same area, same CCD.


-----------
When light shines on an object, a certain number of photons strike and, presumably, reflect off that object and head in various directions. If all the light at one point equaled 10 photons, just to pick a number, the angle of the lens does not change that. That is why the inverse square law does not apply to the distance to the camera, only to the placement of the light source.
-----------

ok.. so say we have 100 photons hitting an apple =)
and they are reflected by the surface of the apple in different directions.

the case of the "light colector"

case A:
Lets say we have lens A with surface light collecting area of "Sa"
and we get 10 photons collected and focused on a CCD with fixed surface area, with our normal lense.

caseB:
lets say we add a larger light collector B with double the surface area. Assuming a even photon distribution we will now gather (about) 20 photons coming from that apple, which will be focused on the same CCD.

so in case A we get 10 photons on our CCD, in case B we get 20.
(more photons -> more light)

=====================

the case of the "open eye" =)

similar to above we collect 10 photons from the apple.

if we have wide angle lenses, the "apple" will look smaller on our image. this is because the lenses have focused the apple on a fewer number of CCD photo sensor elements.

so in CaseA (no extra lenses) we have 10 photons hitting 10 photo sensors, or
1 photon per sensor.

in CaseB (with the larger lenses attached) we have 10 photons hitting 5 photo sensors. Or we have
2 photons hitting each element.
======================
bottom line:
no matter type of optics you attach to your cam, if you have larger lense infront, extra light gathered from the lens will reach your CCD and lower the lux.

I call this elemental logic =)

Once again: at no time did I say your ccd gets larger. The buckets are an analogy for lenses, not ccds.

When you use a larger front end on a lens you gather more photons but you are assuming these photons all reflect and are focused on the same point. This does not happen unless you increase the source light.

Take a garden hose with a spray attachment. Aim it at the aforementioned bucket. Say a quick spray releases 100 droplets (photons) and 10 land randomly inside the bucket. Using a wider bucket may catch 20 droplets. You have captured more drops (light) but, reverting back to the lens, the lens will attempt to focus the photon spray at the ccd. It cannot focus all the photons perfectly since they are all different distances from the ccd. 10 droplets in the smaller bucket (lens) can be brought together (focused) better than 20 droplets in the wider bucket. (See circle of confusion, sort of).

The light reflected at any point on the apple never changes just like the water from the hose never changes but you can collect more of it. However, no point in the bucket will get any wetter just by using a larger bucket. Equally, no point on the ccd will get any brighter just because you use a wider angle bucket, er, lens, which, I thought, the original question was.

Rob, I don't think I can explain this any simpler... =/

-------------
When you use a larger front end on a lens you gather more photons but you are assuming these photons all reflect and are focused on the same point. This does not happen unless you increase the source light.
------------

when you use larger front end lens you DO gather more photons... (which means you gather more light), I agree... the next part makes no sense.
I do assume you focuse them on the same "point" (i would say area) .. - the CCD
the more photons you have the more photons you focus on the CCD, the more light you get on the CCD.

----------------
Take a garden hose with a spray attachment. Aim it at the aforementioned bucket. Say a quick spray releases 100 droplets (photons) and 10 land randomly inside the bucket. Using a wider bucket may catch 20 droplets. You have captured more drops (light) but, reverting back to the lens, the lens will attempt to focus the photon spray at the ccd.
-----------------
at least you agree that you will capture more light.
now you have to tell me how you will lose part of this gathered light.
in the example you need half of the light to somehow "diasppear" in order to have only 10 of the 20 droplets reach the CCD.


-----------------
10 droplets in the smaller bucket (lens) can be brought together (focused) better than 20 droplets in the wider bucket.
-----------------
what you are saying is that you can focus better 10 photons than the 20, and that when you focus the 20, 10 somehow disapear?
I hope you see how fallacious this suggestion is....
(even if you were out of focus you'll still get 20 photons on the CCD, even if they are not arranged well - blury image)

I would suggest you go back to my previous post and think about it a bit more. I hope you get it this time...

good luck.

ps. i was trying to figure out what exactly you are thinking...
you should know, you don't "focus" photons you redirect them. so if you redirect them. maybe you think that you cannot redirect them all on the CCD?... and half of them "spil" outside the CCD?
(this of course does not happen...)
i give up... g'luck again, i don't think there's a point of more examples.

I hope you weren't trying to explain anything to me! I was trying to explain this to you. You're previous post is inaccurate. But since you choose not to read any further I, too, will stop posting.

yep.. there's no point of going on about this.

I just wanted to see a test, so if anyone has the ability to make it, please try it and post the pics.
10x in advance

ps. Rob, I see that you were only explaining it to me. Thats why you didn't even think about what I was saying. No point to continue on that path.

ps2. for those who are still following.. and still confised.. you can try thinking it this way: when you gather more light you gather more energy, unless yout lens charge the battery pack, they'll transmit... project the higher light energy onto the CCD. And even "unfocussing" cannot make you lose the gained energy.

George, your original question was this: "Is there any change in the LUX sensitivity of 953/gs100k if you use large wide angle lenses? (like Aspheron)?" And your answer is, no.

Frank, did you try it? or you are taking a blind leap of faith? =)
(since what Rob says is incorrect)


make 3 shots,
1-original setting, lens
2-attach the wide angle lens, and make a shot from the same location
3-with wide angle lens, move the cam closer so you get more or less the same scene in the frame

do this in low light conditions, and post the pics =)

post the pics...

be the one who shows some facts :)

ps. the change and increased light will be there, but it may not be enough to have visible difference in this specific case of dv953 and Ashton lens, but untill you test it you'll never know.

I had already mentioned that I didn't notice a LUX improvement when I was trying wide angle adaptors on my cams in Leo's dimmly lit downtown store. I tried the Tiffen wide (37mm and 43mm), and a couple of Raynox models. If I discovered that a wide would improve the LUX requirements of my cams, I would have bought a couple of wide angles years ago. If you're not happy with your PV-DV953's LUX requirements, sell it, and buy a MX3000 or better, a VX2000. I'm sure they're both easy to find in the used market. Just a couple of weeks ago there were 2 MX3000's up on e-bay; someone posted these links here, several threads down from this one. If you don't want to spend that kind of money, look for a used Panasonic PV-DV852 or an Optura 100MC. That's what I would do, but I still have my old but trusty DVL9500's for "low light" shooting. :-))

See: http://www.dvinfo.net/conf/showthrea...threadid=24781 - I'm asking too. But the trick isn't with in an adaptor but with the cam instead. :-))

Frank, the idea was to have mush larger lens, not one thats about the size of your cams. I think 37mm is about your cam own lens (even if it's a wide-angle, there will be no change at all, same size - same light collector).

Thanks for the suggestion, but I'll probably get GS400 =)
and then if I have to, I'll make a camp-fire on the living room's floor, for extra light :)

Actually, placing yourself or your subject or one or two 60 watt light bulbs in the right place can make all the difference with your footage. Never mind the campfire in the living room. I did that, and my aunt who was baby sitting me and my brother at the time thrashed us real good, after she put out the fire. My Aunt's still alive, bless her soul. :-))

=) too bad you hadn't had a cam setup for the "camp-fire" that day :))
it would had been something

That was 46 years ago. No miniDV back then. :-))

hey.. next time you have no excuse! =)
(you have a DV cam now)

I'll have to wait for old age dementia to set in. It won't be long now. :-))

hehe.. looking for other excuses, ey? ;-)

you start the fire now, I'm coming over with marshmallows in a few min. :)

I do have one other excuse: no fire insurance. :-((

George, since you have the cam why can't you test it yourself?

BTW, you tell people I'm wrong and, as a professional trying to help you understand, I'm insulted. You don't seem to be able to comprehend what you are being told and want others to do your work for you.

I'm between cams right now. I'm waiting for Gs400 to come out this Jul. So I can't test it. If I could I would have done it. =/

The problem is that is not correct.

The CCD of GS400 will be different, and will not produce the same results as dv953. When I get the cam I'll test it, and maybe post pics if I don't forget.

It's not the wide angle, it's the extra mm of the lens that will make a difference.

The error you make comes from the fact that you thing of the extra lens only in turms of providing wider angle. This would be right if the wide angle lense you put on the cam is the same size as your original lens (like Frank had done with the 37mm wide angle). In this case you would be right, but we are not, and never talked about this case. We are talking for lens with larger surface area.

When I mentioned 37mm threads, I meant 37mm threaded wides with my 37mm threads on my 2 cams; and 43mm threaded wides for my 1 43mm threaded cam.

oh... ok

excuse my mouse-drawing:
http://www.alienminds.ca/extra-lens.jpg
(very simplified)

case2:
http://www.alienminds.ca/extra-lens2.jpg
(wide-angle same size, same amount of light from apple, but focused on smaller surface)

George i had the same belief as you and i still dont know if i understand fully. A lot of the posts on here clearly show that people haven't really read what each other are saying they just keep on saying the same thing all along. I don't think anything has been gained from all this C!@p. anyways can anyone read my post on the first page and explain to me why i am wrong. and i think the arguement is that with bigger lens you catch more light like the bucket. so more light means more energy and therefore since that light is being focused on the ccd the same size no matter what then wouldn't/shouldn't it help. why and why not,. lets forget what has been said and the tension that has built and start fresh from this. Thanks. It just seems logic from my explanation of a 2x converter.

Thanks

Justin

Convertor lenses are not designed to change lux ratings. I think in this thread, there is a lot of confusion between what we all learned at school about (simple) lenses and complex optical systems on the other hand . In practical terms, one should know that a convertor "lens" is an a-focal optical piece of glass which only changes the angle of the incoming light on the main camera lens. The amount of light hitting the CCD remains determined by the main optics. The convertor lens gradually "prebends" the incoming light, just like mirrors which can bend the light. The larger front area is needed for redirecting the light without vignetting. Because the convertor lens is a-focal ((=infinite focal lenght ) the captured light isn't concentrated into the main optics, so the larger area doesnt make any difference. Only powerfull raytracing programs can show exactly what happens in detail.