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Enviro 500

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On 7/24/2020 at 7:54 PM, PCC Guy said:

I'm not really sure what the best place to ask this is, so I'll try here.

What is the best way to figure out ISO?

So far, in my travels with my SL3, I have found out two valuable pieces of information: f/8 is the sharpness sweet spot on both of my lenses, and I am too clumsy to shoot anything slower than 1/500, so I try to keep my shutter fast, too - for buses, anyway... there is some room for negotiation with other types of photography, in terms of both settings.

This of course means that my bus photos, without a good ISO boost, would be quite dark, but I'm not really sure what the best way to figure out what ISO I need is (auto ISO tends to not be sufficient). Though I am partial to shooting through the viewfinder, one of the limitations is that there is no preview in there as to whether the photo will be correctly exposed or not, and that has bitten me in the ass on more than one occasion. I shoot RAW, so fortunately I've yet to lose an actual photo, but I find that relying on RAW to make up for my lack of skill is a crutch, and it's becoming a bit of an embarrassment. If I'm in one spot and I'm going to be there for a while, obviously I can change to live view, set up a good shot, and then be confident that most of my photos will be fine, but for locations where I might be pointing the camera at various locations, such as at an intersection, it typically happens that auto ISO is insufficient: one location is fine and the other is overexposed, and there's no quick way to correct this without missing the shot. On a few occasions, the auto ISO bumped me up as far as 1250 on a bright, sunny day!!

Does anyone have any advice?

I'm usually around 1//500 at f.8 when I'm shooting 100 or 125 ISO film.

1/500th at f.8 is a very reasonable middle of the road combination of shutter speed and aperture opening, definitely not pushing any boundaries either way, so you shouldn't need an extreme ISO setting to get there.  Heck, the rule of thumb for press photographers was "f.8 and be there!"  Anyhow, I'm strongly leaning towards M. Parson's first point about the camera's metering pattern.  Keeping 1/500 at f.8 under decent daylight without an extreme ISO setting really makes me question how the camera's metering is interpreting the scene.  If it's got multiple metering modes, have you made sure it's not set to spot meter?  If you have a predominantly white bus or predominantly dark grey asphalt road centre of frame when you set up your shot and your camera spot meters that and calculates exposure, it'll throw it off for sure.  Centreweighted averaging is the way to go if possible.

It might be worth borrowing a second camera and duplicating the setup or buying/borrowing a calibrated grey card and compare your camera against a known source of second opinion to see if what it's doing is reasonable.

On 7/25/2020 at 9:55 AM, M. Parsons said:

A few considerations. 

Metering mode. I keep mine usually on spot or center weighted metering. A lot of what I shoot are blue buses or black locomotives. I find evaluative metering will cause an under exposure of the vehicle I'm after, so, I prefer to meter off of what I'm shooting as opposed to the whole scene.

Definitely.  The way buses have a lot of white in the paint schemes now and black locomotives can cause skewed meter readings used to bite me all the time when I was starting out.  Centerweighted averaging would tame most scenes unless it filled too much of the frame.  The trick I used when that was going to be a problem was to go to the left or right and meter the surroundings, minus the subject, to get a good average value and use that instead of getting caught by mismetering something that was skewing a good chunk of the frame I was going to take a picture of.

On 7/25/2020 at 9:55 AM, M. Parsons said:

A lot of the time when it comes to choosing ISO/ F stop combinations it comes down to intuition and experience. I also don't stick with F8.0. My 16-50mm F2.8 lens is quite decent at F2.8 and my new 18-135mm F3.5-5.6 is quite good as low as F4.5, so I'll usually open the aperture and then increase ISO. Off the top of my head, I'd say I probably do 400 on sunny days, 500-640 on a cloudy bright day, 640-1000 on a cloudy day for moving vehicles. Stationary vehicles will always get 400 and F8.0. 

I try not go below 400 ISO. I don't want to run into a "oh shit" situation when I realize my ISO is completely wrong for the scene. At least at 400ISO on a cloudy day I can salvage a shot by quickly hitting the thumbwheel and opening the aperture all the way. 

Youch!  To this film shooting guy those are really hot ISO settings!  100 is about the fastest I used to like to go.  Kodachrome 25, 64, various E6 at 100, colour negative film is what I used the most of with some of Fuji's now discontinued 400 speed slide film.  I still have some unused rolls in the fridge if the need arises.  125 and 400 speed black and white film is always neat.  For some reason, I don't object to film grain in black and white pictures but it always drove me up the wall in colour; it's kind of interesting that my reluctant top value for ISO is your bottom boundary!  It's also interesting how with digital, the mindset is different since all values can be changed for each frame.  That isn't possible with film where you're committed to an ISO for a whole roll and you have to live with shutter speed and aperture being the two parameters you can work with unless you're in a shooting medium format and can switch film backs loaded with different speed film (the Bronica that was in my minivan when it was stolen) or sheet film.

I find digital photography's closer to shooting video than film.  I'd really prefer having a waveform monitor display, or better yet waveform monitor plus vectorscope, available because you can then see exactly how your scene's exposure is falling into the dynamic range that's possible to capture which is important considering how brutally unforgiving digital clipping is.

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