Shooting with a long lens is blurry

[antihero]

taken from
http://photo.net/bboard/q-and-a-fetch-msg?msg_id=007YEP
Peter Groen, Feb 29, 2004; 01:39 p.m.

Ofcourse it is YES. Think logically people. The shaking of the camera is of course amplified because of the multiplier factor.
As an example: let's assume you make a picture using a Canon 1Ds and a Canon 10D (1.6 multiplier), both with the same lens:
You shake both camera's 1 mm up and down.
For the 1Ds, this means that the picture is being shaken for 1mm of the 23.8 mm of the sensor's height (sensor is 35.8 x 23.8 mm). That means that the picture is being blurred for 1/23.8th part of it's total height: 4.2%
For the 10D, this means that the picture is being shaken for 1mm of the 15.1 mm of the sensor's height (sensor is 22.7 mm x 15.1 mm). That means that the picture is being blurred for 1/15.1th part of it's total height: 6.6%

Ok, which picture will be 'blurrier'? That of the 10D of course, and exactly 1.6 times blurrier than the picture taken with the 1Ds.

So, yes, you should multiply the 1/focal length rule with the multiplier for digital camera's...

well....using (my) logical thinking, the crop factor is exactly that. It CROPS the viewed image, it doesn't magnify it. The fact that the image is cropped only gives the effect of it being magnified.

So if you took a blurred shot on a full frame camera, would you not in fact see LESS blur if the image had a x1.6 crop (only because part of the image has been cropped out)? Or have I completely got the wrong end of the stick?

 

[sportysnaps]

So if you took a blurred shot on a full frame camera, would you not in fact see LESS blur if the image had a x1.6 crop (only because part of the image has been cropped out)? Or have I completely got the wrong end of the stick?

no - you would see more of the blurr as it is magnified by 1.6 times.
the real key here is this is a rule of thumb :rules:and if you can hold the camera really steady - using a tripod/monopod/beanbag etc then its not a problem :bang:

 

[digitalfailure]

Well I'm glad i'm a full frame owner, my focal length is exactly whats on the side of the lens

 

[jefferybond]

Very rough rule of thumb is that you need to use a shutter speed that is 1 / focal length.

ie.

300mm , shutter speed = 1/300s
70mm , shutter speed = 1/70s

Of course, if you have an APS-C sized sensor (eg 400d), which has a 1.6x crop factor, then you need to factor this into the shutter speed calculations.

Duh, just realised all this has already been mentioned previously!


300mm x 1.6 = 480mm, which means ~ 1/500ths

 

[StewartR]

Well I'm glad i'm a full frame owner, my focal length is exactly whats on the side of the lens

Your focal length is ALWAYS exactly what's on the side of the lens, whether your camera is full-frame or not.

:bang:

 

[mole2k]

I fail to see how the 1.6 crop comes into it really. Nothing is being magnified there isnt any extra lenses changing the focal length. All an APC sized sensor does is cut off a bit around the edges of a full frame picture.

By the logic your applying saying you need a faster shutter speed then your saying that a sharp shot on full frame brought into photoshop then cropped to the 1.6 frame size could be blurry.

As a side note i've never really followed the rule for shutter speeds as I find I can hold a lot lower but I do agree its a great ruling for people begining to give them an idea of a shutter speed that they should be able to be handholding stuff at. I quite regularily shoot 1/60th at 300mm indoors with acceptable results.