What Dynamic Range To Expect From A Canon G9 ? And UV?

[abrogard]

Please excuse my ignorance if I've got the question wrong.

What I mean is what range of light and dark should the camera correctly deal with in one exposure.

i.e. A sunlit picture with shadows. And clouds in the bright sky. If exposed correctly for the sky will it also correctly display the shadows?

It is my belief that cameras are somewhat limited in this aspect and I am calling it 'dynamic range', hope that's acceptable.

And I believe it has something to do with pixel size in the camera sensor. But I am very vague about this.

I generally think that bigger pixels can handle a greater range because they can absorb more photons. And I see 'the range' as effectively being the difference between 1 photon and the maximum.

So if one photon represents a shadow and the pixels can take 10 photons then the range is brightness between 1 and 10.

But it it can take 100 photons then the range is ten times as good as that. It can handle ten times the brightness.

That's my pretty vague understanding of it all.

My Canon G9 seems to struggle to properly record sunlit scenes here in Australia. I generally get what seem to be underexposed pictures. They are like that because there is much sky in them and the sky is bright.

If I then process them to bring up the detail in the shadows - which may simply be the wall of a building - then the detail in the sky gets washed out - fleecy clouds, say.

So what range should I expect from this particular camera?

And years ago I had a Pentax Spotmatic and always used a UV filter on it.

Would a UV filter be appropriate for this camera in this context?

My (again vague) understanding is that UV light is very energetic and will therefore quickly
'overload' or fill up a pixel in a sensor. Unnecessarily because we don't need to record UV radiation because we can't see it anyway.

So cut it out with a filter and the pixel doesn't get overloaded so easily making it appear as a 'darker' subject. Allowing the camera to lengthen the exposure. Which lightens the shadows.

Can the members tell me what I should expect from this camera and how much of my understanding is wrong and perhaps put me right?

[DanK]

Your terminology is correct: dynamic range refers to the range of brightness a sensor can capture. It is most often measured in EVs (exposure values). The range in EVs is the same as the range in f-stops. Small sensors like yours generally do less well than larger sensors, but one review I found suggests that the G9 does respectably well as long as you stay at base ISO--a range of a bit over 12 stops. The range deteriorates quickly as you increase ISO.

It isn't uncommon for brightly lit, high contrast scenes to exceed the dynamic range of the camera. In such cases, if you don't want the whites or blacks to be clipped, you have to bracket exposure, taking two or more photos exposed differently, and then combine the two in software.

You needn't worry about UV light. Most digital cameras have filters to filter out most UV light, and the glass lens elements filter out more. The result is that most digital cameras are much less sensitive to UV light than film is. Most people who use UV filters on digital cameras do so for physical protection of the lens, and some people (I am one) use them interchangeably with simple protective filters, which are just clear glass with anti-reflective coatings but without UV protection.

[Manfred M]

If you have the original Canon G9; that camera came out in 2007 and if you are writing about the G9 x Mark II, it's a couple of years old. Which model are you using? The G9 X Mk II has a 12.5 stop dynamic range at base ISO whereas the G9 has a 10 stop dynamic range at base ISO. Crank up your ISO and both cameras drop fairly quickly; so shoot with the lowest ISO you can to maximize the camera's dynamic range.

You can look up the camera performance on the DxO Mark website:

https://www.dxomark.com/Cameras/Cano...t-G9-X-Mark-II


If you shoot in harsh sunlight at mid-day and have very heavy shadows, you can definitely get into trouble with the dynamic range. If you shoot raw, then you have a bit more latitude than if you are shooting JPEG.

Camera sensors are sensitive to both near UV and IR, so camera manufacturers include both a UV and IR filter as part of the filter stack that sits on the sensor. For all intents and purposes, a UV filter is unnecessary on a digital camera.

If you are shooting a scene with a lot of sky, the camera will tend to underexpose. If your camera has an exposure compensation control, try dialing in +1 to see if that helps. The problem is the way any camera's reflective light metering system works. They are fine for an "average" scene, but if the scene is too bright, the camera will underexpose and if it is too dark (think if a night time shot), it will overexpose.

[William W]

Canon G9 . . . what range of light and dark should the camera correctly deal with in one exposure. i.e. A sunlit picture with shadows. And clouds in the bright sky. If exposed correctly for the sky will it also correctly display the shadows? It is my belief that cameras are somewhat limited in this aspect and I am calling it 'dynamic range', hope that's acceptable.

Results of testing by DxO (on Landscapes Scenes) indicates that the G9 has a Dynamic Range of about 10 Stops.

***

In my response on the other site, where you’ve been posting, you indicated some confusion in my meaning. I’ll attempt to clear that up.

In really simple and very general terms:

> (modern) Digital Cameras have a Dynamic Range of about 10 Stops give or take.

> A screen can reproduce about 5 Stops (I mean this comment to refer broadly to a range of 'screens' which people generally use to 'have a look at my photos' e.g. laptops, phones, tablets, TV screens - additionally doing that in uncontrolled lighting).[** SEE FOOTNOTE]

> An exceptional quality Print has a Dynamic Range about 8 Stops.

The technique required, seeks to capture as much of the scene's dynamic range in the best quality that you can so then you can 'squish' all that Dynamic Range into the lesser Dynamic Range of a Screen image or a Print image.

There are some basic tenets:

> To PRESERVE the HIGHLIGHTS, generally you need to expose to the right (ETTR) as much as possible.

> To PRESERVE the SHADOWS, generally you need to give them as much exposure as possible.

In some circumstances maybe you will need to blow-out some of the very bright highlights.

These practices are primarily based on the fact that there is a known amount of the highlight area which can be recovered in Post Production; on the other hand, the very dark areas (the SHADOW AREA) tend to show excessive NOISE when their levels are increased in Post Production.

‘recovering the Highlights’ and ‘bringing up the Shadows’ effectively is the ‘squishing’ that I referred to earlier – basically your putting 10 Stops of DR into 5 Stops of DR.

***

In the other thread I wrote

“The technology in your G9 can handle a very large Dynamic Range of Light: much larger a Dynamic Range than what can be displayed on any screen.

I think that you need to get your head around two basic concepts:
> only ONE portion of any photograph can be ‘correctly’ exposed
> the trick is choosing what portion of the photograph to ‘expose for’ to allow you to make a Final Image (after Post Production) that is acceptable to your Initial Concept (Artist’s Concept).

“‘Old Film Cameras’ had NO Dynamic Range at all – the Film did: and (probably) you sent the film to a lab and then the Darkroom Technician did all the Post Production for you.
With Digital technology it is usually the Photographer who does the Post Production, hence:

- “the trick is choosing what portion of the photograph to ‘expose for’ to allow you to make a Final Image (after Post Production) that is acceptable to your initial concept.”


The sentence “> only ONE portion of any photograph can be ‘correctly exposed’”, seemed to be confusing to you.

What I meant is: you need to choose what part of the scene you are going to ‘correctly expose’ – that is what part of the scene is the basis for the selection of your EXPOSURE PARAMETERS (i.e. Av Tv and ISO).

For example, in a Landscape scene you might ‘expose for’ the Trees, so the detail in the shadows is well rendered in the final image, or for a Sunset, you might ‘expose for’ the bright hues on the horizon, and be happy to render the trees in deep shadow without any detail.

In the other thread I also recommended that you BRACKET your exposures.

Note that:

> selecting a different METERING MODE on your camera
> pointing the camera at different parts of the scene
> NOTE - zooming in/out is effectively the same as pointing the camera at different parts of the scene

will often result in the camera's Light Meter suggesting to you to use different exposes parameters. This is an important concept to understand: the Camera does NOT, in the final analysis, chose the exposure parameters to use - you do. To make that choice, I think that we need to understand the suggestions that the camera is giving to us and why the camera is giving us those suggestions.

WW


** Footnote: I was just reminded that a Calibrated Studio Monitor (as used for critical Post Production) typically will render about 10 Stops DR and I have amended this commentary to clarify my meaning, i.e. that I was not talking about Calibrated Monitors. Thank you, Manfred for the note.

[xpatUSA]

While following the discussion with interest, I must admit to being envious of the DR numbers for non-Sigma cameras!

I had one my earlier Sigmas (an SD9) tested by the well-respected Bill Claff - it was just over 9 EV. Still, when I check most of my shots in RawDigger, they rarely exceed 5-6 EV before the raw histogram starts breaking up due to binning at the lower level. No big deal to me, because I only view on my monitor and it's brightness is cranked down to about 100 cd/m^2 (dim room).

Always a surprise how human vision makes up for deficiency in what we're looking at ...

[William W]

. . . Always a surprise how human vision makes up for deficiency in what we're looking at ...

And, what the are latitudes used for any testing procedures? Especially those 'tests' that may find their way as an adjunct to sales' propaganda.

WW

[Clactonian]

I have several older cameras that have been rubbished by the DXO tests when it comes to dynamic range but they still are capable of producing beautiful images if I get all the parameters right. Do we concentrate too much on specifications and not enough on aesthetics and getting good exposures?
All equipment has its limitations. Learn to live with them by taking photographs not reading data sheets.

[DanK]

I have several older cameras that have been rubbished by the DXO tests when it comes to dynamic range but they still are capable of producing beautiful images if I get all the parameters right. Do we concentrate too much on specifications and not enough on aesthetics and getting good exposures?
All equipment has its limitations. Learn to live with them by taking photographs not reading data sheets.

Well, yes and no. Correct settings can avoid clipping only if the scene does not exceed the total dynamic range of the sensor. If it does, there is no way that correct settings can compensate; you will run out of room at one end or the other. Of course, one can always bracket.

It is a matter of what types of photography one does, but I don't run into this problem all that often.

[Clactonian]

Well, yes and no. Correct settings can avoid clipping only if the scene does not exceed the total dynamic range of the sensor. If it does, there is no way that correct settings can compensate; you will run out of room at one end or the other. Of course, one can always bracket.

It is a matter of what types of photography one does, but I don't run into this problem all that often.

I don't disagree, that is why I said that one must learn to live within the limitations of the camera. I also suspect that I'm not alone in discovering that my own limitations influence results more frequently than those of the camera.

[DanK]

I'm not alone in discovering that my own limitations influence results more frequently than those of the camera.

well, that's certainly true of me...

[rpcrowe]

There are ways to work around your problem of burned out skies.

1. Should be obvious... Include as little as possible of the sky... Shooting areas that are front lit (sun at your back) might also reduce the exposure range... Avoiding foregrounds that are dark or backlit is also a consideration...

2. Shooting in RAW might give you a bit of extra latitude...

3. I don't know the parameters of the G9 but, all of my Canon cameras (several DSLR cameras and the SX50-HS) allow a three shot HDR burst. That along with some PP "might" be a partial solution to the burned out skies problem... However all images are not HDR appropriate. Keeping the camera as steady as possible is essential in shooting HDR images. A tripod or, at least, a monopod might be helpful to accomplish this.

4. It is "possible" to shoot with filters on the G9. The use of filters with this cameras is a bit convoluted as it is with my SX50 HS. However, a CPL and or a graduated neutral density filter is always a fall back to reduce the overall dynamic range of an image. A 43mm filter is accepted by the G9. I "think" that a lens tube adapter is needed https://www.amazon.com/Lens-Tube-Ada.../dp/B01DD487GI
on which a 43mm filter can be mounted. I don't know how easy this system is to work with in real life shooting scenarios. The availability of GND filters is sort of limited in the 43mm size. Perhaps a step up ring (43mm - 49mm or so) might be possible to use.

That is how to surmount the problem in-camera. There are various ways to work around it in various editing programs. I don't know which program or programs you have access to but, I do know that you can use a GND type effect in Photoshop and that you can select the sky or the foreground pretty easily in the NIK software suite.

I just received an email from Serge Ramelli touting the Luminar editing program. I don't know anything about this program but, if it is decent it may help...
https://www.google.com/search?rlz=1C...39.ums5NqKDrmE

You can do HDR composites on Photoshop and NIK software has a module HDR Efex Pro which allows HDR compositing. I seldom, if ever, work with HDR so I cannot give any advice on which software to use. Some cameras even allow multi image HDR compositing in-camera; although some only allow this when shooting in JPEG...

We tend to say "The photographer is a greater limitation than the capabilities of the camera." As the song from the operetta "Porgy and Bess"goes, "It ain't necessarily so". As a trite example of this, it would be difficult for a person to get good imagery of a gymnastic event in a high school gymnasium (traditionally HS gyms are under lit) with a camera that doesn't have high ISO capability, has a slow aperture and relatively sow focusing capability (especially in low light); all of which parameters are quite usual for P&S or bridge cameras and not terribly unusual for lower end DSLR cameras with kit lenses...