Photo Tech Talk-Basic Concepts in Photography, Part 2

Mellody Farm-Gate of Heaven

 Shutter: how many different speeds can your shutter mechanism go?

    One! It’s the second curtain that determines the shutter speed by starting earlier (faster) or later (slower), that determines your faster or slower shutter speed.

What’s your camera’s flash Sync Speed?

    You have to know your flash sync speed! Some cameras will NOT let you set a "too-high" shutter speed when you have a flash attached, so you remain within the sync speed. Others don't, so you have to stay at the maximum or lower. Some examples of sync speed: Sony A6300 is 1/160, Sony A7RII is 1/250, the Canon 6D MkII is 1/180th. If you go beyond you will get a black band in your image.

Rear (second) curtain sync?

    Second (Rear) Curtain: Flash fires at the end of the exposure. Use Second (Rear) Curtain Sync setting for slow shutter action shots, 1/20/second or slower, to get the image on the right side of the example below (which looks cool, front curtain sync doesn't work here).

ISO (correctly pronounced "Eye-So"

    "ISO measures the sensitivity of the image sensor.” Yes, you can think of it that way, but really the sensor doesn't actually get more and less sensitive. After the image is taken, and the voltage is captured, and before it is stored on your card, the camera boosts the gain on the signal, (like turning the volume up on your amplifier) from your Base ISO to whatever ISO you’ve dialed in. So ISO is “how much you’ve chosen to boost the signal, given by the sensor, so you can get a desired exposure.” Say you chose 800, you have a Canon so your base ISO is 100, so 200, 400, 800, your camera says multiply that by 3 and then store it!

“Base ISO”, “Native ISO”, “Extended ISO”

“Base ISO” is one number, like 100 (or 200 for some Nikons). Native ISO is a range, in the Sony A7RII it’s 100-25,600. Extended ISO is from Native ISO up to the top, to 102,400 ISO on the Sony. Don’t ever shoot that! Since extended ISO values don’t provide any image quality benefit — yet they do make it easier to clip highlights— you’ll get a dynamic range penalty by using them!

Yes, shooting at higher ISOs will introduce more noise in your image, but ALSO REDUCE your dynamic range. Modern cameras can get great images up higher, so even ISO 12,800 is not a problem (just increase your noise reduction slider a bit).

ISO Invariance

This feature benefits low-light shooters, who have to use higher ISOs to get a proper exposure. Some camera models from Sony, Nikon, Fuji and Olympus (but not Canon), are what we call "ISO Invariant". This means there is no penalty in noise if you use a lower ISO when you shoot, and then brighten a photo in post-production, rather than increasing your ISO in-camera. There is a huge benefit: you will get MORE DYNAMIC RANGE, and potentially more latitude in the photo’s brightest highlights.

File Types

    JPEG (Joint Photographic Experts Group), was invented in 1992!

    Heif is a better replacement for jpg, now supported by Adobe’s products, like Lightroom and Photoshop, among others. Jpg is 8-bit, Heif (on an iPhone) is 10-bit. How much more information does a 10-bit file have over an 8-bit file? 4X, each bit doubles the amount of information. According to MPEG, which created it, and Apple, HEIF images should be half the size of a JPEG image file, but with the same—or better—picture quality.

    But HEIF isn’t just about file sizes. HEIF images offer a variety of features that aren’t available in JPEG, like transparency. The iPhone’s camera can capture photos in 10-bit color, so HEIF’s 16-bit color maximum is a worthwhile upgrade over JPEG’s 8-bit color. To use on iPhone, got to Settings/Camera/Formats/Select “High Efficiency” (not “Most Compatible”, that’s jpg).

Speaking of Apple

    Apple Pro RAW combines the benefits of Apple’s Deep Fusion and Smart HDR tech with the flexibility of a Raw file format for editing.

    It's not a new format, simply regular DNG files that use little known features in the DNG file format specifications, as well as a few new features Apple worked with Adobe to implement in the new DNG 1.6 specification. A ProRAW file, captured with the default 12-bit data, is roughly 25MB.