Lightnings taking a ride

by ceinmart

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bio website mattgrum.com
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visits member for 4 years, 11 months
seen 4 hours ago

Jul
29
reviewed Approve How was this photo taken
Jul
29
comment How was this photo taken
@AndersD by low ISO value I mean 100-400
Jul
29
revised How was this photo taken
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Jul
29
answered How was this photo taken
Jul
27
answered Is the “typical print size” still relevant when judging sharpness of a photograph?
Jul
27
revised Is it coincidence that Nikon F lenses can fit a Canon EF body (with an adapter)?
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Jul
27
revised Is it coincidence that Nikon F lenses can fit a Canon EF body (with an adapter)?
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Jul
27
answered Is it coincidence that Nikon F lenses can fit a Canon EF body (with an adapter)?
Jul
27
comment Why don't people care any more about shutter speed accuracy?
@akram The problem was quite obvious, in aperture priority mode shots were coming out massively underexposed, but only at high shutter speeds like 1/1000s or 1/2000s, so I knew it couldn't be the metering. At very fast shutter speeds the rear curtain starts to close before the first curtain is fully open so any synchronisation issue between the curtains will be very obvious whilst not presenting much of a problem at slower shutter speeds where the rear curtain being 1mm ahead of where it should be would not change the exposure significantly.
Jul
22
comment Why does Sony say that a 35mm lens is “35mm equivalent when used with an APS-C camera?”
@shennan it seems you're not getting what happens when you put a lens on a smaller sensor - you get a smaller image, which has the same field of view as a longer focal length on a larger sensor. The lens is not "restricted" to an APS-C sensor, it's just if you put it on full frame you'll get darker corners. They could fix that but the lens would be heavier and more expensive. But even if they did that, it wouldn't change how it behaves on a smaller sensor, it would still give the same field of view as a 52.2mm lens would on full frame.
Jul
22
comment Why does Sony say that a 35mm lens is “35mm equivalent when used with an APS-C camera?”
@shennan No, interchangeable lenses are always sold by their actual focal length. This lens is a 35mm lens. The EFL when used with an APS-C sensor is 52.5mm
Jul
22
comment Why does Sony say that a 35mm lens is “35mm equivalent when used with an APS-C camera?”
@shennan Sony haven't fudged anything, the lens is called a 35mm lens because it's focal length is 35mm. It's 35mm when mounted on a full frame camera, it's 35mm when mounted on an APS-C camera, it's 35mm when it's in the box and not mounted on any camera at all... the focal length helps you work out the FOV, but it doesn't define the FOV by itself. Sony state the focal length that gives the same FOV on a full frame camera, to help people who understand the relationship between focal lengh and FOV on full frame cameras estimate the FOV of the lens on APS-C cameras.
Jul
22
comment Why does Sony say that a 35mm lens is “35mm equivalent when used with an APS-C camera?”
@shennan It's an APS-C lens because the image circle it illuminates is only big enough for an APS-C sensor. When mounted on a full frame camera the corners will be black.
Jul
22
comment Why does Sony say that a 35mm lens is “35mm equivalent when used with an APS-C camera?”
They name it as a 35mm lens because it is a 35mm lens, i.e. it brings parallel lines into focus 35mm behind the second principal plane. This is the definition of focal length, a property of the lens only, one that doesn't change when mounting the lens on different cameras. Focal length does not by itself define the field of view.
Jul
22
awarded  Strunk & White
Jul
22
answered Why does Sony say that a 35mm lens is “35mm equivalent when used with an APS-C camera?”
Jul
22
revised What are the anomalies in this picture of earth?
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Jul
22
revised What are the anomalies in this picture of earth?
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Jul
22
comment What are the anomalies in this picture of earth?
@NormLDude a simple paragraph would have sufficed under the pic that was posted on Flickr "May not be exactly as shown here" or "The quality of this image is 44% of the original" - the artifacts you're referring to are completely invisible until you perform a huge shadow boost, so why on Earth would they need to mention it? Should the same disclaimer be placed next to every JPEG image published anywhere in the web? Images NASA posts on Flickr are for PR purposes, not scientific analysis.
Jul
22
comment What are the anomalies in this picture of earth?
@NormLDude "There seems to be a lot of definition (3d)/depth to this 'anamoly'. The other circles surrounded by tiny circles are pretty interesting also." that is all completely explained by my answer - the 3D shapes come from the primitive building blocks which are all based on [co]sine waves.