18 megapixels on a 1.6x crop camera - Has Canon gone too far?

"OldBoy" wrote in message


[...]

Better to use pixel pitch :-)
www.dxomark.com :
Pixel pitch (in micrometer)
a380 - 5.1
a900 - 5.9
5D - 8
5DII - 6.4

The 7D has probably 4.3 as pixel pitch

The 50D has a pixel pitch of 4.7. Since the 7D also uses the Digic 4
processor (albeit 2 of them for speed) I wonder what they've done to the
sensor to reduce noise.

The main features I would like to see:

1) in two related parts ... a light histogram that actually
represents the absolute raw data. The two parts are one, a histogram
that shows the recently taken picture, on the LCD screen, as present,
just completely unmodified, and two, a histogram, somehow displayed
as an overlay in the viewfinder, that shows a histogram of what the
various exposure sensors are currently reading, in real time so
it changes as you move the camera view around, and as you change the
exposure in manual more of change the exposure offset.

2) At least one focus sensor that covered a really really small area
and was really accurate.

Doug McDonald

On Thu, 03 Sep 2009 10:42:43 -0500, "mcdonaldREMOVE TO ACTUALLY REACH
wrote:

The main features I would like to see:

1) in two related parts ... a light histogram that actually
represents the absolute raw data. The two parts are one, a histogram
that shows the recently taken picture, on the LCD screen, as present,
just completely unmodified, and two, a histogram, somehow displayed
as an overlay in the viewfinder, that shows a histogram of what the
various exposure sensors are currently reading, in real time so
it changes as you move the camera view around, and as you change the
exposure in manual more of change the exposure offset.


I have found that CHDK's real-time "Zebra" overlay for under/over-exposed
areas much more beneficial to real-world photography than any histogram.
(Named as such in CHDK for the crawling diagonal stripes to highlight these
areas, one of its many display options.) This type of exposure assistant
allows you to see in real-time what areas of your image might be
underexposed or overexposed. Many times a feature in your image doesn't
need to retain any detail. And at times you actually want to blow-out
certain highlights or lose detail in some shadows (i.e. silhouettes). To
more clearly understand what I'm talking about, refer to:

http://chdk.wikia.com/wiki/CHDK_firm...bra_parameters

Another nice feature is that you can select any color for either light or
dark limit, including many subtle transparent shades so it becomes
unobtrusive to focusing and framing. I personally use a light transparent
red for highlights and a pale transparent blue for shadows. Allowing me to
rapidly differentiate both extremes at the same time in real-time in the
FOV. It also allows you to set the sensitivity threshold for highlights and
shadows independently.

If you like there's also an RGB Zebra mode (not shown on the CHDK Wiki
pages, but appears in the downloadable PDF manuals) that will show you
blown highlights on each color channel. Red, Green, and Blue appearing in
their respective colors if being maxed-out. If both Red and Blue are being
blown-out, then that part of your subject is displayed in Magenta. If Red
and Green then in Yellow. If Green and Blue then that area is overlaid with
Cyan. If all 3 color-channels are overexposed then Black is shown on that
area. I find this RGB Zebra mode a bit overkill, but it does come in handy
for some technical photography where color reproduction has to be as exact
as possible, ensuring that you don't pin the needle on any one or more
color channels.

[One thing left out of the CHDK manuals. I have found that I have to set
the overexposure sensitivity threshold to no lower than 16 when using RGB
Zebra in order to enable all seven possible color combos to display
properly. Testing this sensitivity limit on my monitor while it displayed a
Granger Calibration Chart to ensure there were no gaps in the RGB blow-out
limits for any combos of colors. Otherwise just the main R, G, and B,
channels, and only partial channel-combos will show blow-outs with
sensitivity numbers lower than 16.]

A simple live-histogram only tells you that some areas of your image might
be lost, not which areas of your composition. For photography, where
composition is everything, a common histogram is almost useless. A
histogram is great for people who do nothing but pixel-peep, edit, and use
their cameras as technological conversation starters. But for real
photographers it'll never show you what you really need to know, the exact
parts of your subject that might be under or overexposed. If I had a choice
between two identical cameras, one showing a full RGB histogram the other
having a Zebra-Mode capability, I'd easily choose the one with the Zebra
mode after now having years of experience with using both methods for
real-world photography. Luckily, any CHDK camera has both available in many
incarnations, the parameters of which you can easily and quickly modify in
the setup options menu 'til your heart's content.

On Thu, 03 Sep 2009 10:42:43 -0500, "mcdonaldREMOVE TO ACTUALLY REACH
wrote:

The main features I would like to see:

1) in two related parts ... a light histogram that actually
represents the absolute raw data. The two parts are one, a histogram
that shows the recently taken picture, on the LCD screen, as present,
just completely unmodified, and two, a histogram, somehow displayed
as an overlay in the viewfinder, that shows a histogram of what the
various exposure sensors are currently reading, in real time so
it changes as you move the camera view around, and as you change the
exposure in manual more of change the exposure offset.


I have found that CHDK's real-time "Zebra" overlay for under/over-exposed
areas much more beneficial to real-world photography than any histogram.
(Named as such in CHDK for the crawling diagonal stripes to highlight these
areas, one of its many display options.) This type of exposure assistant
allows you to see in real-time what areas of your image might be
underexposed or overexposed. Many times a feature in your image doesn't
need to retain any detail. And at times you actually want to blow-out
certain highlights or lose detail in some shadows (i.e. silhouettes). To
more clearly understand what I'm talking about, refer to:

http://chdk.wikia.com/wiki/CHDK_firm...bra_parameters

Another nice feature is that you can select any color for either light or
dark limit, including many subtle transparent shades so it becomes
unobtrusive to focusing and framing. I personally use a light transparent
red for highlights and a pale transparent blue for shadows. Allowing me to
rapidly differentiate both extremes at the same time in real-time in the
FOV. It also allows you to set the sensitivity threshold for highlights and
shadows independently.

If you like there's also an RGB Zebra mode (not shown on the CHDK Wiki
pages, but appears in the downloadable PDF manuals) that will show you
blown highlights on each color channel. Red, Green, and Blue appearing in
their respective colors if being maxed-out. If both Red and Blue are being
blown-out, then that part of your subject is displayed in Magenta. If Red
and Green then in Yellow. If Green and Blue then that area is overlaid with
Cyan. If all 3 color-channels are overexposed then Black is shown on that
area. I find this RGB Zebra mode a bit overkill, but it does come in handy
for some technical photography where color reproduction has to be as exact
as possible, ensuring that you don't pin the needle on any one or more
color channels.

[One thing left out of the CHDK manuals. I have found that I have to set
the overexposure sensitivity threshold to no lower than 16 when using RGB
Zebra in order to enable all seven possible color combos to display
properly. Testing this sensitivity limit on my monitor while it displayed a
Granger Calibration Chart to ensure there were no gaps in the RGB blow-out
limits for any combos of colors. Otherwise just the main R, G, and B,
channels, and only partial channel-combos will show blow-outs with
sensitivity numbers lower than 16.]

A simple live-histogram only tells you that some areas of your image might
be lost, not which areas of your composition. For photography, where
composition is everything, a common histogram is almost useless. A
histogram is great for people who do nothing but pixel-peep, edit, and use
their cameras as technological conversation starters. But for real
photographers it'll never show you what you really need to know, the exact
parts of your subject that might be under or overexposed. If I had a choice
between two identical cameras, one showing a full RGB histogram the other
having a Zebra-Mode capability, I'd easily choose the one with the Zebra
mode after now having years of experience with using both methods for
real-world photography. Luckily, any CHDK camera has both available in many
incarnations, the parameters of which you can easily and quickly modify in
the setup options menu 'til your heart's content.

Chris Malcolm wrote:

My cheap radio trigger has full shutter functionality, half and full
press.


Forgot about that - I have the Cactus trigger, works quite well.

David

David Kilpatrick writes:
D300S = 0.94 / 1.5 = 0.626 apparent size
7D = 1.0 / 1.6 = 0.625 apparent size

Ah, I didn't think about the smaller Canon sensor. I guess it's not
really indicative of an upward trend in VF sizes then ...

-Miles

--
Advice, n. The smallest current coin.