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Tema: ISO nominal en nuestras eos 750D

  1. #1

    Predeterminado ISO nominal en nuestras eos 750D



    Buenas tardes.

    Viendo varios videos, veo que mencionan "ISO nominal". Entiendo el concepto. Es decir es la iso a la que la camara se maneja mas comodamente en cuanto a sensibilidad de luz. Tirando un poco de google.... leo que en las camaras Nikon, el tema anda sobre los multiplos de 200 (200,400,600), en canon por otro lado en multiplos de 160 (160, 320, 640). Es decir que para nuestras canon seria la iso nominal 160. El problema radica en que me pongo en modo manual, le doy al boton de la ISO y cual es mi sorpresa cuando veo que la rueda hace moverse la ISO en multiplos de 200, con lo que me es totalmente imposible acceder a los 160 o 320 que supuestamente es lo mejor para canon.

    Como se entiende esto?. Ya de paso.... Cual es la ISO nominal en la 750D?.

    Un saludo.

  2. #2

    Predeterminado

    La ISO nominal es 100. Yo no me complicarÃ#a mucho con esos temas técnicos. Recuerda que los valores en fotografÃ#a se relacionan casi siempre por doble o mitad:
    ISO#100-200-400-800...
    v#1/30 1/60 1/125 1/250 1/500...
    f#1-(1.4) -2- (2.8)-4-(5.6)-8-(11)-16 (22)

  3. #3

    Predeterminado

    Gracias. Lo pregunte por que creo que lei que algunas canon andaban mejor a otros valores que no fueran los mutiolos de 100. Pero no recuerdo ahora cuales

  4. #4
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    Predeterminado

    Lo has visto aquí: https://hipertextual.com/archivo/2012/01/isonominal/ o aquí https://www.canonistas.com/foros/showthread.php?t=337757




    If you’ve tinkered around with Canon HDSLRs, then you may have heard that its best to shoot video using sensitivity settings that are multiples of ISO 160. I’ve been doing this because I have heard folks like Shane Hurlbut and Vincent Laforet say for a couple of years now that that’s the way to do it.

    The results as you can see in the video, are pretty much spot on with what Technicolor has said. Interestingly enough, it seems to me that ISO 640 has about as much noise as ISO 100.

    It also seems that ISO multiples of 125 are specifically bad. ISO 1250 is pretty much comparable to IS0 125!

    It clearly illustrates that best ISO’s to use for video, starting from lowest noise level to highest are as follows:
    160, 320, 640, 100, 200, 400, 800, 1250, 125, 250, 500, 1000, 1600, 2500, 2000, 3200, 4000, 5000, 6400.

    Of course, if you’re shooting low-light and you need a high ISO, the best ones to go for would be: 1600, 2500, 3200 & 5000.

    If there’s plenty light, keep things on ISO 160.

    Multiples of 160 are best, then multiples of 100 and then multiples of 125.




    Mi experiencia es que, al menos las mías y en foto, que vídeo no hago, 5D Mk III y 700D, funcionan mejor con multiplos enteros de ISO base, 100, 200, 400, 800, 1600, 3200, 6400, 12800 y el valor paella. O sea, básicamente lo que cuentan aquí.




    There is a lot of conjecture and misunderstanding about Canon's ISO settings because they use a "real/push/pull" model for ISO settings, rather than using native analog gain for all ISO settings. Canon only uses a standard analog gain (per-pixel amplification) for full stop ISO settings up to a certain high ISO level. So, ISO 100, 200, 400, ..., 3200 are usually achieved by using standard analog signal amplification. After a certain point, really high ISO settings in Canon cameras are achieved via a base analog amp., plus a secondary downstream (post-read/pre-ADC) amp, and possibly a digital boost.

    For Canon cameras pre-5D III generation (i.e. 5D II, 7D, 50D, 550D, etc.) the highest directly amplified ISO settting is usually 1600, after which a combination of downstream amplification, push/pull, and possibly digital boost is used. For post-5D III generation (i.e. 5D III, 1D X, 6D, 70D, etc.) cameras, the highest directly amplified ISO setting is either 3200 or 6400, with the possibility that rebels still top out at ISO 1600.

    Finally, third-stop ISO settings are achieved by using a 1/3rd stop "push" or "pull" using a downstream amplifier after read. ISO 125 is a third-stop "push" of ISO 100, where as ISO 160 is a third-stop "pull" of ISO 200. ISO 250 is a third-stop "push" of ISO 200, where as ISO 320 is a third-stop "pull" of ISO 400. This is why the 2/3rds stop ISO settings in Canon cameras are a little cleaner...the "pull" shoves the noise floor down a little bit.

    The use of push/pull does not make ISO 160, 320, or 640 the "base" ISO...that is an internet myth, breed by conjecture, misunderstanding, and a simple lack of real knowledge of how Canon achieves the necessary signal boost for each ISO setting. All Canon cameras (with the exception of some of the earliest models) use ISO 100 as base ISO.

    It should be noted that Base ISO is different than Unity ISO. Unity ISO is the ISO setting where gain is one, or in other words for every electron of charge, the ADC converts one DU (digital unit). It is pretty rare that Unity ISO is actually selectable, however there is usually a close third-stop setting to unity. What Unity ISO is depends on the camera, the sensor, the full-well capacity, and other factors (Roger Clark has lots of information on his site for popular Canon camera models, and within them he usually derives unity gain, if knowing it is important (some applications may benefit from unity gain).)

    Regarding ETTR, and the use of Base ISO. That is a simple fallacy, really. ETTR simply means Expose to the Right. That's it. There should not be any additional caveats to that. ETTR is a very simple, strait forward rule, and it does not require that one always shoot at ISO 100 or base ISO. I am a Canon user, and rarely shoot at ISO 100 for most of my photography, which is birds and wildlife. Most of my photography is at least ISO 400, more often between 800 and 1600. I generally follow ETTR, regardless of the ISO setting.

    ETTR offers a simple benefit: It puts more of the signal above the noise floor, which improves your editing latitude. ISO 100 is not, and should not be, a requirement for ETTR. Using ISO 100, assuming you have enough light, simply maximizes your dynamic range, within which ETTR is still shifting more of the signal above the noise floor. In Canon cameras, ISO 100, 200, and to some degree 400 have more read noise than all higher ISO settings. The higher read noise floor means you technically get more benefit from ETTR. If you are a landscape photographer, then ISO 100 is probably a given, but it is still not a requirement for ETTR.

    Última edición por flipk12; 31/10/18 a las 20:16:48
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  5. #5

    Predeterminado

    ok. Es lo que me parecio leer a mi

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