making the most of different shooting modes

Canon EF 70-300mm f/4.5-5.6 DO IS USM

09/02/2003 06:09:25 PM · #1

I didn't realise how much I'd start enjoying this photography lark when I got my camera, so I really didn't feel like I wanted manual controls.. nevertheless there are times now when I wish I had more control over depth of field and shutter speed...

so, these are the things my camera lets me fiddle with..

Exposure compensation -2, -1.5 ..thru to.. +1.5, +2 would the camera vary aperture or shutter speed to make this compensation as a rule?

Metering. matrix or spot. I think I'm pretty much ok with what this does and when to use spot rather than matrix..

flash controls on/off/auto etc. obvious

macro on.. off, turn on when shooting at between 20 and 50cm obviously..

scene select (shooting mode): program (auto), portrait, landscape, night, self portrait..

this is the big one.. obviously I know to use portrait when taking a portrait and so on.. the question is how do they bias to depth of field or shutter speed???
my guess is... portrait mode places more bias on having a wide aperture (low depth of field), landscape places bias on a small aperture (high depth of field), night enables a longer shutter speed (up to 2 secs) and probably is biased towards a shorter shutter speed, and self portrait I'd guess is probably biased towards short shutter speed since it assumes you are holding the camera and pointing it at yourself..

Essentially I wish I had more control over depth of field (and to a lesser extent shutter speed) so I'm wondering how best to use the different modes to give me that control.. (I know zooming in gives me less Dof, and zooming out gives me more) are my assumptions right??

Message edited by author 2003-09-02 18:13:03.

cpanaioti

Canon EOS-40D

09/02/2003 07:10:54 PM · #2

Your assumptions are correct about portrait and landscape mode. I would say experiment with each of them depending on what affect you are trying to achieve.

Try a bug macro in portrait mode at full zoom. This should give you the least amount of DOF.

Night mode usually turns on the slow synch for the flash. This is to avoid dark backgrounds.

Canon EF 70-300mm f/4.5-5.6 DO IS USM

09/02/2003 07:36:32 PM · #3

what about the exposure compensation, does the camera compensate via aperture or shutter speed??

cpanaioti

Canon EOS-40D

09/02/2003 07:42:31 PM · #4

Good question. That may also depend on the camera. My guess would be shutter speed. My camera manual doesn't say.

I just tried an experiment. I set my camera in P mode and checked the exposure. Then I set the exposure compensation to +1 and checked the exposure again. The camera changed the shutter speed.

Message edited by author 2003-09-02 19:45:11.

09/02/2003 07:56:42 PM · #5

Originally posted by tomc:

what about the exposure compensation, does the camera compensate via aperture or shutter speed??

Typically it can be either, though shutter speed usually gets kept up to avoid camera shake being an issue.

The mode will probably influence which gets varied though and how - portrait and landscape bias apertures to one extreme or the other (open for portrait, stepped down for landscape)

Landscape modes quite often also fix the lens focus on infinity, though that varies with camera.

Night mode, typically fixes a second curtain slow sync flash mode, to get the background with some exposure (from the slow shutter speed) and a flash to give foreground detail.

I'd suggest trying it out to see which the compensation varies - I'm assuming you get EXIF data you can look at to work out what changed.

irockstars

Canon PowerShot A70

09/02/2003 08:12:40 PM · #6

I love night mode for concert photography, because my flash is super bright. By having a longer exposure it lets in more of the existing light.

Canon EF 70-200mm f/2.8L IS USM

09/02/2003 08:28:31 PM · #7

good idea! I never thought to actually just do a standard test shot and check the exif detail to see what changed!! I'll have ago and post back with results..

yep the night mode seems to do slow sync, I've also read (in a review of my camera) that it also activates a noise reduction thing to avoid the noise associated with long exposures..

one last thing, how does the camera pic ISO speed?? obviously the lower number is better.. so when would the cam choose to increase it.. I notice (from exif data)its used higher ISO speeds even when longer exposure time/wider apertures have been available..
guess I'll do some experiments....

EddyG

Canon EOS-1D Mark II

09/03/2003 09:02:28 AM · #8

Exposure compensation is meant to adjust for the metering. Every meter out there (whether it is built in to the camera or is a handheld light meter) assumes that whatever you are metering is "18% gray". This has been the standard basically "forever", and is the reason why you can buy a "gray card" that is exactly 18% gray at your local photo store for very accurate metering (and color balancing).

Briefly, if you are metering something that is below 18% gray, you would adjust your exposure compensation lower, to account for the fact that you are metering "0% gray" instead of 18% gray. This would decrease the exposure time so the camera doesn't turn your "black" into "18% gray". Similarly, if you are metering something that is above 18% gray, you would adjust your exposure compensation higher, so your picture isn't "underexposed". A good example of this is shooting in the snow. If you meter off the bright snow, sometimes you need to add a full stop (+1) of exposure compensation to make sure you get a nice, white snow.

If you don't have a gray card, a handy (no pun intended) reference that you always have with you and works for anybody (regardless of race) is the palm of your hand. Hold your hand out at arms length so it is in the same lighting (not in your own shadow!), point your camera at your palm (make sure your palm fills as much of the frame as possible), and get a meter reading. Now add 1 stop. (To remeber the "add one" part, think about how many thumbs you see when you fill the frame with your hand. One. Which way is it pointing. Up. So open UP 1 stop. For example, if your camera meters your palm as "f/5.6 at 1/200th second", you should put your camera in "M"anual and set your exposure to f/4 1/200th or f/5.6 1/100th, both of which are equivalent to adding one stop, each with its own pros and cons.) This tip can get you a very good starting point for setting manual exposure. Or you can just rely on your camera's matrix metering. :-)

Exposure compensation is just a quick way of "shifting" the exposure when you know that you need to adjust what the camera is metering.

Sony 16-50mm f/3.5-5.6 E-mount

09/03/2003 09:20:03 AM · #9

Originally posted by EddyG:

While all this is spot on, I think the original question was if you have a camera that doesn't have manual, shutter priority or aperture priority modes, what does the exposure compensation change out of the shutter or aperture to get the desired over or under exposure. Reciprocity means that either could be used, but it has to use one or the other.

jmsetzler

Sony Alpha a6000

09/03/2003 09:25:34 AM · #10

My 707 only adjusts shutter speed for EV compensation.

EddyG

Canon EOS-1D Mark II

Canon EF 70-200mm f/2.8L IS USM

09/03/2003 09:26:27 AM · #11

Damn, you're right Gordon. Just goes to show what happens when I wake up and start reading the DPC forums before getting my coffee. I'm still half asleep! *sigh*

tomc: my apologies that I didn't contribute any worthwhile information to your question. Re-reading the thread, I agree that taking some test shots and looking at the EXIF data would be an interesting way to see how EC works on your particular camera.

09/03/2003 07:32:59 PM · #12

EddyG, thanks for the info on metering anyhow, its interesting and knowing a bit more about how the camera does it means I know more often when to override it..

now.. I've started doing some experiments and I've discovered something interesting..

I've only taken indoor shots so far, (its dark outside) anyway, took two shots in program mode, one with no exposure comensation and one with +2, the exif data for aperture, shutter speed and ISO was exactly the same!! (aperture at max of f/3.1 shutter 1/30) but the second pic was definitely brighter than the first.. so what has the camera done just upped the brightness like my PC would?? this hacks me off a bit.. I can do that myself!

Anyway, I tried just now the same shots but with the flash suppressed.. the camera kept the aperture wide open (f/3.1) and varied the shutter speed, 1/30 at -1 thru to 1/10 at +1..

I'm not sure why the flash is affecting this???

Anyway, I'll try some daytime test shots tommorow hopefully and see what it does..

also anyone know how the cameras choose ISO speed, I'd be interested to find out what sort of rules they use.. seeing as this is something film cameras dont make an automatic choice about..

Message edited by author 2003-09-03 19:36:18.

09/03/2003 09:43:05 PM · #13

It gets a bit stranger with flash because the flash duration/ power can vary to change the illumination, without changing the aperture/shutter.

Typically the flash fires for an incredibly short period of time (1/10,000s or so) This is not the same as the flash sync speed (which is typically of the order of 1/200sec or so and relates to how the flash and the shutter get timed)

So the flash can vary the amount of light, while the aperture/ shutter remain the same for the ambient light, so the exposure comp is probably changing the flash output/ duration, rather than changing anything else.

Daylight or without flash you should see a pretty direct change with different EV values.

09/04/2003 10:47:13 AM · #14

ahh, I forgot the camera might have control over flash intensity/duration I guess that must be it..
Even so the only flash controls I have are auto, red eye, always on, always off, but seeing as I know it uses slow sync flash in night mode then it must have some control over it..