Canon Vixia G60 - What is the base ISO ?

[Casey415]

Question please. What is the base ISO of the Canon Vixia G60 camcorder? I cannot find this info by doing Google search or spec search. Thank you.

[Tim]

Casey415, 

The default is Auto ISO which varies by the exposure level in the scene and is determined based on the needs of the proper exposure level. 

[shadowsports]

From the specs page.

Lens

Canon 15x Optical Zoom, 8.3-124.5mm (35mm equivalent 25.5-382.5mm), f/2.8-4.5

But as Tim said, the ISO is variable.

[wq9nsc]

If you are trying to come from a DSLR (or the even older film camera world), ISO really doesn't have the same meaning or use with video given the curves that are applied to the sensor to achieve desired dynamic range and these systems are instead rated in gain and sensitivity.  Each time you increase video gain by 6db, you are effectively doubling the ISO sensitivity.

I don't know whether Canon produced a different video series for the Vixia G60 but it shares some commonalities with some of the XF models and Canon has an excellent video series for the XF-400 that I watched when I bought mine.  Take a look at this one if there aren't separate videos for the Vixia series because I think you will find it helpful and it will help with video terminology if you are coming from a DSLR world:  https://www.youtube.com/embed/41Smv-2jntc

Rodger

[Casey415]

Hello again,

I'm not sure if either I didn't ask the question properly, or maybe you gave an answer for a different question??

My question is this: What is the base (or lowest?) ISO setting for the G60 camcorder? For example, might the base ISO be 100? or 200? 

Thank you!

[wq9nsc]

See the post from Vortex media in this thread where Doug does an excellent job of explaining why camcorders aren't rated in ISO: https://www.dvinfo.net/forum/canon-xf-series-4k-hd-camcorders/531355-no-iso-known-xf300.html

I am assuming you want to know the base ISO because the numerous sites that go nuts stressing the need to know the base ISO of a DSLR or mirrorless camera when shooting video.

Base ISO for your G60 corresponds to its gain setting of 0db on the gain menu of your camera.  Every 6 db increase in gain is effectively doubling the iso value so if base equivalent ISO is 200 increasing gain to 6db with your gain set control provides an equivalent to ISO 400.  Note that db is NOT a fixed standard but references the change from one value to another so the equivalent ISO of one camcorder set to 0db gain won't necessarily be the same as another model with the same 0db setting.  If you want to shoot at base ISO, then you need to choose a combination of lighting, aperture, and shutter speed that provides proper exposure with the gain set at 0db.

You can use your DSLR to get a pretty close approximation of your camcorder effective base ISO by focusing your camcorder on a static scene (preferably without a lot of contrast and very even lighting) and note what aperture and shutter speed it is using for correct exposure with 0 db gain.  Then set you aperture and shutter speed of your DSLR to the same settings and see where you need to set ISO to achieve a standard exposure.  Your camcorder and camera need to "see" exactly the same scene for this to be even reasonably accurate so frame them both the same.  Your results may be off a little but it should be close enough for your purpose of knowing the equivalent ISO of your G60.

If you have a light meter and a gray scale card, you can more accurately do this calculation but the result should be substantially the same as using your DSLR  I have a Gossen light meter and proper gray scale card but I have never bothered to do so with my XF-400. 

If you are trying for minimum noise, then go with a 0 db gain setting and adjust the other variables for a proper exposure at 0 db.  Increasing the gain of a camcorder is exactly like increasing the ISO of a DSLR, the signal level generated by the sensor doesn't change and the increased gain (aka ISO in digital camera terms) is done by amplifying the signal from the sensor resulting in degraded noise performance. 

Note that with a DSLR, the major factor impacting dynamic range is the ISO (aka gain) and best dynamic range generally does occur at base ISO.  With a camcorder, different programmable "scenes" use a different gain profile mask and these are designed to optimize different aspects but NOT all simultaneously (i.e. dynamic range, noise, etc.) so it is more than just gain level that impacts the quality of the resulting video.

I suspect the base ISO of your G69 is in the 200-320 range but test using your still camera as a reference and see what you calculate.

Rodger

[Tim]

Casey415, 

The ISO equivalent in this camcorder is gain.  The base is 0.0 dB and ranges up to 39.0 dB and can be adjusted in the M mode in 1-dB increments. 

[Inapickle]

Bear in mind also that Wide DR requires higher levels of gain than the Standard picture profile ('Look') - minimum Gain level that can be set in Manual exposure mode is +9db; and likewise the minimum AGC limit in the programmed exposure modes.

[Casey415]

Hi Roger,

Thank you for your detailed input. It appears there's no easy answer to the question. Ideally, what I'm hoping for is to use my Sekonic 308XU light meter to give me an accurate incident light reading of a particular scene. But a prerequisite for the light meter is to enter an ISO value, such as 100, 200, etc, in addition to say the shutter speed (I usually set for 1/50th sec). Then press the button and the meter gives me an f stop value. I can then hopefully use the light meter reading for the G60 camcorder exposure setting. I believe my Sekonic meter also gives EV and LUX values, but I don't know how to translate that for the G60 camcorder exposure.

At this point, I'm simply looking at the G60 LCD screen to see the horizontal exposure bar values and make adjustments to the Gain dB dial accordingly until the exposure bar arrow goes to the middle point for "proper exposure". I also use the Zebra Pattern set for 70% to help determine whether to dial down the Gain dB setting if anything is blown out. I rather like the Zebra Pattern feature, it's similar to the blinking highlight warning indicator on my Nikon and Canon DSLRs. When I used to shoot weddings in the past, the blinking highlight indicator on my DSLRs gave me an immediate alert if the bride's wedding dress is over exposed which would represent 255 exposure value in Photoshop. So far it's been working out decently by using the G60's exposure bar and Zebra Pattern, but I would still prefer an accurate reference point as determined by an incident light meter.

[wq9nsc]

Hi Casey,

You are welcome and it should be pretty easy to use your Sekonic 308 to establish an ISO setting to use. 

Set you G60 up with your desired shutter speed and with the gain set to 0 and adjust the F stop so that the Zebra pattern (and also critically view the results) provides a proper exposure. Then set the Sekonic to the same F stop and shutter setting and change its ISO value until it indicates a correct/standard exposure and this should give you a good working ISO for future use of the meter.  As a guess start with ISO 200 for the Sekonic then modify as necessary depending upon which way it shows the exposure is off.

Once you have established what ISO your G60 provides a 0db then you can reset the ISO level setting for your light meter when you have to use different gain levels.  Every 6 db of additional gain is equivalent to doubling ISO so if effective ISO at 0 db gain is 200 then setting the G60 to +6db of gain would require setting your meter to ISO 400.

I would caution to still check the zerbra pattern when you are using your light meter because of the response "mask" applied to the video sensor output provides a non-linear modification of level differences so you won't to be careful not to blow out important details or have a critical shadow area drop into heavy noise but the light meter will give you an excellent starting point which should be the correct point the great majority of the time.

I can see why you would want to use the light meter for video given what you are doing.  I primarily use mine for setting up the placement and lighting balance of multiple studio strobes but the light meter still is a very useful tool for many purposes.

Rodger