[Wind Chaser]

I finally mounted my 300mm lens on my camera and I'm blown away by the magnification.  My question is... is the crop factor of the sensor portrayed in the viewfinder as in "what you see is what you get" - or do you have to go to live view in order to frame up the shot?

[JohnR]

It's pretty close to what you get. The pro cameras generally are 100% coverage, lesser cameras are 92%, 95%. I've never noticed any practical difference though, and certainly not for hand-held. You may find that once you start cropping to tighten your compositions that the real issue is actually seeing the frame as part of the composition rather than just looking at the subject of the photograph. I've been experimenting with putting things near the edges of the frame to get a better handle on it -

(No it's not sharp, handheld at 300mm through a window and standing in a crowd, but I liked it anyway. Still cropped slightly)

More classic composition, cropped to remove a rock I didn't want on the right. To illustrate the point that for handheld your viewfinder coverage is the least of your worries -

(Just took these yesterday.)

[Wind Chaser]

John,

Thanks for answering my question.  I knew that 35mm SLR film cameras are 1:1 viewfinder to film, but didn't know about the crop factor in DSLRs until just now.  Now that I think about it, I suppose if there were a significant difference, the manufacturers would put an outline in the viewfinder.

Is there a book you'd recommend on composition?

[JohnR]

I knew that 35mm SLR film cameras are 1:1 viewfinder to film, but didn't know about the crop factor in DSLRs until just now.

Actually, film SLRs have the same thing - my F3s are 100% coverage but my FE2 is not. The crop factor for DSLRs is already figured into the viewfinder coverage - if the VF is 100% on a crop camera then you see the same thing that the sensor sees. Crop factor is probably best thought about as simply a focal length multiplier.

There is another factor involved, if you wear glasses, which is that you may not be able to see the full frame. This is related to something called eyepoint which I won't even pretend to understand.

Don't have any specific recs for books about composition... it's a good question though. I'm a bit of a hack, just try stuff, read my fav photo forums, buy a few books on sale about photography... The basic rule though is the rule of thirds. The next thing is (in my experience) get closer. Get the junk out of the picture, make it about your subject. The next thing after that is get further away - think about the background and how it complements the subject. Hey it's a learning process 

FWIW don't be discouraged by your early results with the 300. I'm learning mine still, 150 is easy and fun for me now, 300 is still very challenging. The wildlife photogs using 500 and 600mm lenses really have some skill, no kidding.

[low.pfile]

wind,
your Pentax K-x has a viewfinder that shows 96% of what is captured on the sensor, therefore there will be a bit more in the digital file that what you see through the viewfinder....see this page
http://www.dpreview.com/reviews/pentaxkx/page4.asp

as mentioned above it varies camera to camera. ranging from 90-100% of sensor. The term "Crop factor" has no impact of on the viewfinder area-- it is the relationship of the sensor size to a 35mm negative and/or full frame sensor.

[WerTicus]

Yeah, crop factor is not related to view finder coverage.

your crop factor is 1.5x so your 300mm lens is like a 450mm lens on the Kx (vs 35mm film)
and you can only see 96% of what the file will contain through the view finder. (you get MORE in the file so its not like you need to keep things away from the edges)

[Wind Chaser]

Having experimented I can see that what is seen in the viewfinder is pretty much on par with what the sensor picks up.  I just wasn't sure if the sensor got everything seen in the viewfinder.  Silly me.  150 shots and still sucking, but at least I'm having fun and learning more along the way.

[Wind Chaser]

...your crop factor is 1.5x so your 300mm lens is like a 450mm lens on the Kx (vs 35mm film)

That's a bonus, sort of.  I understand Canon has a crop factor of 1.6x and Olympus a whopping 2x.  Makes buying a good wide angle lens for an entry level DSLR kind of pointless, eh?

[JohnR]

That's a bonus, sort of.  I understand Canon has a crop factor of 1.6x and Olympus a whopping 2x.  Makes buying a good wide angle lens for an entry level DSLR kind of pointless, eh?

Yes, the Achilles heel of crop formats, and a good part (I suspect) of the excitement for full-frame sensors.

I'm sure we will be hearing in short order about the fabulous Pentax lenses that correct this minor problem for anyone who wasn't fool enough to buy into an established Canikon system.

[Wind Chaser]

I'm not a wide angle kind of guy, so I don't mind the cropping and the benefit of having a 300mm lens working as if it were a 450mm lens.  Opened up wide the 18 - 55mm kit lens still gets me down to 27mm.  That's wide enough for me.  Between that and the other lens, I've got enough range to get way beyond what my Nikon point and shoot is capable of.

More lenses are pointless considering my skill at this time.

[Goosepond]

It's always interesting to hear the rationalization of how crop factor cameras give you more than FF cameras by giving you less.

In fact, putting a 300mm lens on a crop factor body does not give you a 450mm lens. The magnification is the same either way. What, in fact, you're getting is the smaller FOV of the 450mm lens without the magnification. What you are getting is packing that FOV on all of the pixels of your sensor, which in rhe end is sorta like getting the magnification.

It just makes sense if you think about it. People are willing to admit the disadvantage of WA lenses on crop bodies but somehow turn that into an advantage on the long end. My question would then be, when does the disadvantage turn into the advantage? Maybe exactly at 50mm? 

Gene

[viggen]

Nikon makes a fanstabulosu 50mm 1.8 lens that sells for a bit over $100.  I can't use it most of the time since the D90's crop factor is 1.5x which turns the 50mm into a 75mm telephoto.  I am stuck using an inferior and much more expensive 17-55mm 2.8 lens.  I bought this before the newer 35mm 1.8 G came out though. 

Crop factoring sucks.

[JohnR]

My question would then be, when does the disadvantage turn into the advantage?

Aha! Actually there is one situation where it's a real advantage, which is for macro, with 1:1 on a crop camera being 24mm across the frame instead of 36mm. Sometimes it really does count

[Wind Chaser]

In fact, putting a 300mm lens on a crop factor body does not give you a 450mm lens. The magnification is the same either way. What, in fact, you're getting is the smaller FOV of the 450mm lens without the magnification. What you are getting is packing that FOV on all of the pixels of your sensor, which in rhe end is sorta like getting the magnification.

A 300mm lens is a 300mm lens.  I understand that.  But because the sensors field of view is reduced, that in effect... is magnification.

It just makes sense if you think about it. People are willing to admit the disadvantage of WA lenses on crop bodies but somehow turn that into an advantage on the long end. My question would then be, when does the disadvantage turn into the advantage? Maybe exactly at 50mm? 

50mm sounds about right.  My kit lens is 18-55mm.  At 55mm it has more zoom than my Nikon P&S with 3x optical zoom.

[Wind Chaser]

Aha! Actually there is one situation where it's a real advantage, which is for macro, with 1:1 on a crop camera being 24mm across the frame instead of 36mm. Sometimes it really does count

I'm confused... for some reason that seems backwards in my mind.

[JohnR]

At 1:1 magnification the area that you are photographing is the same size as the sensor. So if the sensor is smaller, you are photographing a smaller area.

It's the same thing that was said before about the field of view, except that this is one situation where (I think) the crop factor really is an advantage. Having said that, if I actually had a full-frame camera I might think differently... hm... and the higher pixel density in the crop camera means you run into diffraction effects at lower f-stops and you are usually struggling for more depth of field... so in the end I guess it's actually a wash

[Goosepond]

Well, I've got the Canon 100mm F/2.8 Macro lens which at close focus is indeed 1:1. And that has nothing to do with the sensor size behind the lens. With my FF body of course I am getting the entire image circle. Where by definition, that crop body is only getting a portion.

But I repeat, A certain focal length lens has a certain magnification. That doesn't change by changing the size of the sensor behind the lens.

Gene

[JohnR]

Right, but if you are trying to fill the frame with a vewy small object... anyway, it doesn't matter Let's see some pictures, Chaser!

[Wind Chaser]

I'm confused... for some reason that seems backwards in my mind.

I had just woken up and my brain wasn't up to speed... I got it now.

None of the pictures I shot so far are worth sharing.  Hopefully that will change, however I don't get to practice much since I sleep during the day and there is only 7.5 hours of day light up here during this time of the year. 

[WerTicus]

I'm sure we will be hearing in short order about the fabulous Pentax lenses that correct this minor problem...

Hahah

You might try the Pentax 12-24mm f4 or Sigma 10-20mm f3.5
for equal to 18-36mm and 15-30mm full frame coverage.

Or sigma 4.5mm fisheye and 8mm fish eye if you like really wide.  (full 180 view from the former)