Crop Factor

[tomjon]

I recently had a booklet in the D.C. Mag, fresh SLR skills for Spring. How to set shutterspeed to eliminate camera shake,to work out the slowest shutter speed with shooting handheld. For camera's with an APS-C sized sensor multiply this focal length by the crop factor. Now. how do we arrive at the crop factor? If anyone know's please spill the beans, Please, and I was getting on so well as a beginner too. Many Thanks

Tomjon.

[MattUK]

Hi there. It depends on your camera. Nikon crop factor is 1.5x smaller than full frame. Canon is 1.6x

See http://www.kenrockwell.com/tech/crop-factor.htm for details

[GeoffWessex]

Cameras that have no crop factor applied to their lenses have a sensor that is the same size as 35mm film. (aka Full Frame). You multiply your focal length by the given crop factor - so a 100mm lens (or a zoom lens set at 100mm) on a camera with a 1.5x crop factor is effectively operating at 150mm.

Some Canon cameras use the standard APS-C sensor (1.5x crop factor) and some of the older Canon DSLRs use a smaller sensor (though still called an APS-C), with a 1.6x factor. Some of the non-full-frame Canons use the APS-H sensor (slightly larger than the APS-C) which has a 1.3x factor. It's to be hoped that anybody buying a full-frame camera would know about this..... it's one of the best reasons for getting one.

[OldBoy]

Originally Posted by tomjon

I recently had a booklet in the D.C. Mag, fresh SLR skills for Spring. How to set shutterspeed to eliminate camera shake,to work out the slowest shutter speed with shooting handheld. For camera's with an APS-C sized sensor multiply this focal length by the crop factor. Now. how do we arrive at the crop factor? If anyone know's please spill the beans, Please, and I was getting on so well as a beginner too. Many Thanks

Tomjon.

I don't think crop factor has a bearing on the slowest shutter speed you can handhold. As crop factor just alters the field of view and not the length of the lens, so a 300mm lens on a full frame gives you the same reach as on a crop factor camera. The slowest shutter you can use depends on how steady you can hold your camera. Some can only manage 250s whilst others can manage 1/4 second or less.

[thefonz78]

I think he is referring to the rule of thumb guide that the zoom should equal the shutter speed. For example if shooting at 100mm shutter speed should not be under 1/100 sec. The calculation was for 35mm so does not take into account the crop factor of 1.5. So using this principle you should not shoot at 100mm slower than 1/150 sec handheld. To complicate further, modern zooms have image stabilization which lets you shoot about 4 stops slower which would let you shoot 100mm at 1/18 my camera does not shoot at 1/18 closest is 1/20. I hope my calculation are correct?

[ian clark]

Tomjon
I suspect you are fairly new to this game.
Try not to get bogged down with all the jargon.
Crop factor is the difference in size of your cameras sensor area to one that is equivalent to a 35 mm film strip
Nikon aps are 1.6
As for what shutter speed to use depends on the subject and light basically the faster the subject the faster the shutter speed to enable any motion to be frozen less light slower shutter speed
Initially I would suggest no slower than 1/60-1/125 till you develop your own technique for holding the camera i. e. braced body locked elbows hold your breath and SQUUEZE the shutter release.
If you still find you get camera shake perhaps invest in a monopod or tripod.
we could go on about aperture death of field iso etc etc
best advice get out and practice get of the auto settings AND PLAY if you dont like the shot change settings and try again
THE BEST advice i got was to ALLWAYS watch the histogram and apply exposure compensation if shadows or highlights are clipped this one thing has greatly improved my images straight out of the box as i am not a geek and find computer enhancement , allthough very good; rather boring

[thefonz78]

Nikon,Sony and Pentax Crop factor is 1.5 Canon is 1.6 olympus is 2.0

[GeoffWessex]

thefonz - as I wrote above - Canon cameras are not all 1.6x factors - they use at least three different sensor sizes in their DSLRs..... Other than their Full-Frame cameras they make - APS-C (but slightly smaller than most others and with a 1.6x crop factor - e.g. 600D, 1100D, 7D, and most others; they also have APS-H (1.3x - e.g. 1D MkIV). A few of the oldest EOS cameras had a standard sized APS-C sensor, giving 1.5x.

ian clark... Nikon's APS-C cameras are all 'standard' and have 1.5x crop factors... e.g. D5000, D7000, D300, D90 etc - I can't find one that has a 1.6x factor.

OldBoy... that's an interesting point you make about the crop factor not making any difference to the old 'rule of thumb' of not shooting at a fraction where the denominator is less than the physical focal length. I can see what you're getting at but surely the 'optical' focal length changes with the crop factor, if not the physical focal length, and therefor you'd apply the rule to the effective length? I think it would need some technical reference to back that up.

[thefonz78]

GeoffWessex's Yes i'm aware of the 1.3 crop but this was only on the 1d models which is a pro camera and quite a few years old. I made the assumption tomjon is new to photography and wouldn't be using a 1d so left this out.

What camera do you use tomjon?

[tomjon]

Thanks for your very prompt reply fella's. Im beginning to see the light at last. Iclicked on MattUK's Ken Rockwell and it was very good reading I've just about got it now.All that remains now is practice and more practice, change settings and try again.So thanks again for all your replies.It's nice to be able to turn to someone to ask these questions Thanks.
Tomjon.