FF Equivelant Question...

Started 2 months ago | Questions thread
Great Bustard Forum Pro • Posts: 45,635
Re: Answer:

cwatson1982 wrote:

Great Bustard wrote:

cwatson1982 wrote:

Great Bustard wrote:

Mark Ransom wrote:

Messier Object wrote:

Great Bustard wrote:

40Eridani-Vulcan wrote:

So then the 12-45mm f/4 that I have is actually a pretty slow lens at f/8

It's an f/4 lens that is equivalent to a 24-90 / 8 on FF. This means it has the same [diagonal] angle of view as a 24-90 lens on FF, has the same DOF as an f/8 lens on FF, and puts the same amount of light on the sensor as an f/8 lens for FF, thus the same noise that FF would have at f/8 for the same scene and exposure time.

and yet . . .

the term "slow" is usually referring to Exposure Values, not DoF nor Signal:noise.

Talking about slowness and total light in the same sentence can be (my opinion) confusing to some

As I see it, an f/4 MFT lens is just as fast as any other f/4 lens on any format. The differing DoF and noise figures are effects of the differing sensor sizes and have nothing to do with the lens being fast or slow. Note above (my bold) that 40Eridini used the term "slow lens"

I'm always amused when people refer to F-stops as being fast or slow. The speed of light doesn't change, and the lens itself isn't moving. It's the associated shutter speed that's fast or slow; a large aperture lets you use a fast shutter, while a small aperture forces you to use a slow shutter.

I can use whatever shutter speed I want regardless of the aperture. So, the aperture size doesn't "let" me use a faster or slower shutter speed. It affects the noisiness of the photo for the shutter speed I use.

I'm not sure why you are even stating that as it is completely irrelevant to the act of taking photos. I can take an image at f1.8 with a telephoto pointed at the sun with a 1s exposure or 1/2000 at f22 in an unlit room, neither will produce a useful image. No one cares about lens speed in so far as noise goes outside of it's ability to produce a proper "image lightness" as you call it, without having to raise ISO to maintain acceptable shutter speed.

I'm saying it because using an f/1.8 lens on mFT doesn't "let" you use faster shutter speeds than an f/3.6 lens on FF.

Sure it does, with constraints on both DOF and a minimum necessary shutter speed.

So you're saying that if 17mm f/1.8 1/200 ISO 400 represents the "ideal" settings for a particular photo with mFT that I can't use f/3.6 1/200 ISO 1600 on FF? Why not?

It may not get you better noise performance (depending on specific sensors) but it will at the least give you similar noise performance as the FF system for a given "image lightness" and if it's a static scene where camera motion is the issue you may even be able to use less ISO than equivalence implies just due to superior in use IBIS.

Huh? I'm asking why "using an f/1.8 lens on mFT doesn't 'let' you use faster shutter speeds than an f/3.6 lens on FF". I assure you, whatever exposure time you use at f/1.8 on mFT, I can use at f/3.6 on FF.

Do I lose the noise advantage if I do so? Yes. But I can do it, and I would do it, if DOF and motion blur mattered more than a less noisy photo. So, no, f/1.8 on mFT absolutely does *not* "let" you use faster shutter speeds than an f/3.6 lens on FF.

I regularly get sharp .5 second exposures with a lowly e-m5 II at 120mm equivalent, my girlfriend can't do that with a z7 and she is steadier than I am to begin with. Same with wide dark landscape shots hand held, our last trip she was at 5k ISO when I was at 1600. I didn't need as high a shutter speed to get sharp photos.

Well, I can't speak to your girlfriend and her Z7. I mean, c'mon now, let's not go down that path.

If your mFT camera has superior image stabilization to a Z7, then, for sure, there are circumstances that will give your mFT camera a noise/DOF advantage over the Z7.  However, using f/1.8 on mFT absolutely does *not* allow mFT to use faster shutter speeds than f/3.6 on FF.

Post (hide subjects) Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow