joer Loc: Colorado/Illinois

You are correct but does it really matter. So many people take excellent photos and don't have a clue about angle of view, depth of field, etc..

dgkli

Thanks for the hints!

dgkli

OK, so say I have a micro 4/3rds sensor. Shooting with a 25mm lens @ f/2.8. So, the equivalent angle of view is full-frame 50mm. Here is where I get confused. Are you saying that I would get the same depth of field as with a full-frame 50mm @ f/1.4? That confuses me since I know in general larger sensors are supposed to give you more bokeh (I just wanted to see what happens if I use that word).

My gut feeling is the other way around maybe? That at equivalent angle of view for M4/3 vs FF you would need a lens 2 stops slower. Or would that be 1-stop slower (1-stop allowing in twice as much light, or is that a separate issue entirely)?

Totally confused by this. :?

GoofyNewfie Loc: Kansas City

You would need a 25mm at f/1.4 on a m4/3 camera to equal the depth of field of a FF camera with a 50mm at f/2.8.
1.4- 2- 2.8 two stops, right?
That's one reason FF cameras (or even larger formats) give you an advantage in shooting portraits or anything requiring shallow depth of field. Finding ultra-fast lenses may be futile and expensive. One of my favorite lenses way back was the 180 f/2.8. You would need a 90mm 1.4 to give the same results on a m 4/3 camera. Leica has a 90mm f/2:
http://www.adorama.com/LC902MAU.html?utm_term=Other&utm_medium=Affiliate&utm_campaign=Other&utm_source=rflAID021866

Now to that other thing: Bokeh is not the same as depth of field.
It address the quality of the out of focus areas, not that they are out of focus.
You can't get MORE bokeh, just less distracting or pleasing bokeh. It's a subjective thing that isn't a quantity, it's a quality.
Words like creamy, swirly, smooth, neutral, etc are used describe bokeh.

It seems to be a boutique word used by fauxtographers so they can sound cool.... I dislike the word "capture" almost as much.

More here:
http://kurtmunger.com/bokeh_samplerid22.html
From the link, for those who never open them-
"...bokeh is how out-of-focus points of light are rendered, meaning the character of the point of light, not how far out of focus a background scene is."
Read it, then never mention it again.
:lol:

dgkli

Ah, thank you on both counts. I will never mention the b-word again, and not having read many threads on this forum yet, I have not been exposed to the pitfalls of the incorrect use, or perhaps any use, of the word. I, in fact,had not encountered the word until recently, when I became more interested in photography after many years of just playing around.

I will make the comment that it's easy to understand why people misuse it, because so many articles out there either also misuse it, or at least are very fuzzy about what it means.

Thank you for going easy on me.

GoofyNewfie Loc: Kansas City

The 'net is an interesting place to get info.
You can find just about any answer you want to hear.
...and some of it is even right!

PhotoArtsLA Loc: Boynton Beach

You are speaking of image circles formed by lenses. The larger image circle of the full frame SLR/DSLR (+/- 24x36mm film/sensor size) when used on the smaller "DX" sensors of many DSLRs, creates the "crop factor."

If the crop factor is 1.5, then a 100mm FX lens on a DX sensor will have its image circle cropped, giving the DX camera the apparent field of view of a 150mm lens on the FX camera.

In essence, the crop factor DOES give you the longer focal length, e.g. the 100mm FX IS a 150mm DX lens, but more than that, this psuedo 150mm will perform better than ANY 150mm put on the FX camera.

Why?

Cropping in on an image circle is a good thing, because the central portion of the image circle, as cropped, delivers the best performance any lens can muster. Only at the edges (limit of the image circle) does a lens show its weaknesses. If a cropped 100mm, as a 150mm FX equivalent, is used on a DX DSLR, then that photographer, without effort, has improved his or her photos and enjoys a bigger telephoto effect.

This, of course, holds true for ANY FX lens on a DX camera, from wide to telephoto.

Were you doing technical photography, all your calculations would be based on the crop factor, as in, the 100mm would be referred to as a 150mm.

To sum up, have both FX and DX cameras and enjoy more creativity with your FX lenses.

Talk about a crop factor... Seeing the Moon filling the frame brings wonder.

SteveR Loc: Michigan

PhotoArtsLa...It is only magnified because it takes up a larger percentage of a smaller sensor. The image is not, in fact, magnified.

boberic Loc: Quiet Corner, Connecticut. Ex long Islander

OK thats why it is called a crop sensor. If FF cameras were the same price as crop there would be a more cogent argument in favor of them. But many of us (me included) can't afford to pay for the full frame so we are limited to a crop sensor. In any event unless you need more than an 11x14 print with the high megapixal count of todays cameras the argument is moot. It's a distinction without a difference.

SteveR Loc: Michigan

I agree with you boberic. Crop cameras are outstanding. I was blown away with the first shots I took with my D7000. I couldn't resist the temptation of the 36 megapixels of the D800, however, and I enjoy shooting with it above the 7000. One advantage of the high resolution is not just larger prints, but the possibility of better crops (I discovered this when shooting whooping cranes at a distance). I've not used the D7100, but it may rival the D800 in this capability, although the pixels are smaller. The bottom line is that todays DSLR cameras, from bridge cameras to full frame cameras offer amazing possibilities.

PhotoArtsLA Loc: Boynton Beach

Of course the image is not magnified. The image circle always stays the same. Cropping in via a smaller sensor creates the "apparent magnification." The image circle of an FX lens extends far beyond the edges of the small DX sensor.

Huge amounts of image information is unused, "cropped," creating an image using the best portion of the FX image circle. This is why it is the equivalent of a better lens with more apparent magnification, exactly the same as putting a longer lens on a FX camera, but without the image quality boost.

Cameras like the D800 offer the choice of FX or DX sensor areas in shooting. The specific intent is to offer D800 users longer effective telephoto imaging. It is pointless in wide angle because the wide angle FX lenses would be used in FX mode to maximize the wide.

photo169 Loc: Chicago,ILL

See this guy knows what he is talking about.
:thumbup: Give him credit for knowing his stuff. :thumbup: :thumbup: :thumbup: End of effective focal length discussion!!!!!!!! :-) :-) :-)

GoofyNewfie Loc: Kansas City

He knows what is important.