Got my new Canon L series lens - help!

Gregeff · 18 Sep 2008 at 15:11

Netvyper said:
Care to summarise these two for n00bs like myself?

To avoid visible camera shake always take photo with shutter speed of at least 1/effective focal legnth. So if using a 135mm lens on APS-C you want to be at least 1/200 sec to avoid camera shake. Hence why the OPs photos where blury, he was using a shutter speed which was about 400times slower than it should have been for sharp hand held photo!!!

Sunny 16 rule: If it's sunny, the correct exposure should be about 1/ISO Speed at f/16.

Mr Jones · 18 Sep 2008 at 15:13

Gregeff said:
To avoid visible camera shake always take photo with shutter speed of at least 1/effective focal legnth. So if using a 135mm lens on APS-C you want to be at least 1/200 sec to avoid camera shake. Hence why the OPs photos where blury, he was using a shutter speed which was about 400times slower than it should have been for sharp hand held photo!!!

Sunny 16 rule: If it's sunny, the correct exposure should be about 1/ISO Speed at f/16.

Didn't know about the Sunny 16 rule, but now I do

Raymond Lin · 18 Sep 2008 at 15:13

If you are shooting at 200mm then best of the shutter speed at 1/200th of a second, if its 50mm then 1/60th of a second.

Sunny 16 rule can be found online easy enough.

Netvyper · 18 Sep 2008 at 15:20

Gregeff said:
To avoid visible camera shake always take photo with shutter speed of at least 1/effective focal legnth. So if using a 135mm lens on APS-C you want to be at least 1/200 sec to avoid camera shake. Hence why the OPs photos where blury, he was using a shutter speed which was about 400times slower than it should have been for sharp hand held photo!!!

Aye, that is what I thought for this one, was told it the other day & my next trip had a lot less blurred shots

Gregeff said:
Sunny 16 rule: If it's sunny, the correct exposure should be about 1/ISO Speed at f/16.

^^ One to remember, thankyee sir

A.N.Other · 18 Sep 2008 at 15:53

Netvyper said:
Care to summarise these two for n00bs like myself?

Have a read of the bit about ISO, aperture and shutter speed in the sticky. For more information, buy the book "understanding exposure"

domthecondom · 18 Sep 2008 at 16:25

Hand held at 1/2 seconds :| if you ever get a super focused pic at them shutter speeds you are my hero (hand held that is)

Logic Zero · 18 Sep 2008 at 16:40

domthecondom said:
Hand held at 1/2 seconds :| if you ever get a super focused pic at them shutter speeds you are my hero (hand held that is)

I just got a super sharp picture with a 2 second exposure whilst my mum held my hand. Am I your hero?

L0rdMike · 19 Sep 2008 at 12:14

D.P. said:
Unless he has full frame he would need 1/320 if you use the rule of thumb.

I would aim for 1/400s at 200 on a Canon body (1.6x crop).
I can get away with 1/200 but the success rate drops in halve

Pretty sure that is wrong, 200mm is 200mm on any lens, just isnt cropped on full frame.

Gregeff · 19 Sep 2008 at 12:40

L0rdMike said:
Pretty sure that is wrong, 200mm is 200mm on any lens, just isnt cropped on full frame.

by that logic you could hand hold a compact camera at 1/5th of a second because it has a 5mm lens

TBH it's all about pixel densities and the rule is only very rough...

D.P. · 19 Sep 2008 at 14:10

L0rdMike said:
Pretty sure that is wrong, 200mm is 200mm on any lens, just isnt cropped on full frame.

No I'm right. A 200mm lens merely refers to the distance from the front element to the sensor plane/film. The effective focal lenght on a crop sensor will be larger.

To avoid camera shake you have to reduce the relative speed of the light moving across the sensor which is dependent on sensor size and focal length.

at 200mm shoot at 1/350. Or ignore me and get soft images (unless you are really steady).

Raymond Lin · 19 Sep 2008 at 14:15

D.P. said:
No I'm right. A 200mm lens merely refers to the distance from the front element to the sensor plane/film. The effective focal lenght on a crop sensor will be larger.

To avoid camera shake you have to reduce the relative speed of the light moving across the sensor which is dependent on sensor size and focal length.

at 200mm shoot at 1/350. Or ignore me and get soft images (unless you are really steady).

200mm is still 200mm

It's just the perspective is the same as a 300mm lens because of the crop.

Mr Jones · 19 Sep 2008 at 14:29

Raymond Lin said:
200mm is still 200mm

It's just the perspective is the same as a 300mm lens because of the crop.

Yea but think about it, because it's at 300mm lens perspective, a small increase in movement is also magnified.

A quick example off my head is take 2 rulers. 1 short and 1 long. Hold the short ruler with 2 hands and tilt it about 10degrees with the lower end at your eye level.

<) /

Now hold the long ruler the exact same way and tilt it the same 10degrees.
<)///
<) /

You get my point there?
I'm just trying to show you, the sensor will see the same as the 35mm, any increase in "shake" movement is magnified by it.

Galaxy · 19 Sep 2008 at 14:50

A crop sensor simply reduces the field of view relative to a full frame. So a 50mm on a 1.6x crop has the field of view of an 80mm on a full frame, provided subject distance remains the same.

Imagine looking through a full frame viewfinder with a black frame of card around the lens, this is what you'd see with a crop camera.

Hope that clears things up.

Raymond Lin · 19 Sep 2008 at 15:07

It's not magnified.......

It's call a crop body, not a magnified body.

It looks more zoom in because you are only seeing the central bit.

Mr Jones · 19 Sep 2008 at 15:39

Raymond Lin said:
It's not magnified.......

It's call a crop body, not a magnified body.

It looks more zoom in because you are only seeing the central bit.

I'm not saying it is a magnified view, I'm saying the hand shake is magnified when the crop sensor is looking down a 200mm which is perceived as e.g. 320mm (1.6x)

EDIT:
I'm not very good at phrasing myself, so please excuse if my previous post was confusing. This guy did a better job at it me thinks;

The effect though is definitely dependent on focal length, even if it must also depend on other factors. All else being equal, the smaller field of view from a longer lens will magnify the appearance of any camera shake we may induce through hand holding. If a given lens sees a particular angle of view measured in degrees, a 0.1 degree angular movement of the camera will result in things shifting by by a certain amount. If the angle of view that lens sees decreases due to zooming it to a longer focal length, that same 0.1 degree camera movement will be a greater portion of the total angle of view, resulting in a more apparent blurring of the image.

From here.

JBuk · 19 Sep 2008 at 16:10

Mr Jones said:
I'm not saying it is a magnified view, I'm saying the hand shake is magnified when the crop sensor is looking down a 200mm which is perceived as e.g. 320mm (1.6x)

EDIT:
I'm not very good at phrasing myself, so please excuse if my previous post was confusing. This guy did a better job at it me thinks;

From here.

I'm not sure I agree with the opinions on that site

a 200mm lens is still 200mm if its on FF or crop. I don't quite see how a cropped sensor can percieve more shake when all its doing is using less of the image circle from the lens

If theres scientific proof then fair enough but I never ever multiplied the focal length by the crop factor on my old 20d, if I was using my 70-200mm at 200mm I would go for a minimum of 1/200 , never had any problems with it at all

Raymond Lin · 19 Sep 2008 at 16:35

You are still only seeing the center part of the same view, by your reasoning should the center part of a photo from a FF camera more susceptible to camera shake where the outer 40% doesn't ?

Mr Jones · 19 Sep 2008 at 16:37

Raymond Lin said:
You are still only seeing the center part of the same view, by your reasoning should the center part of a photo from a FF camera more susceptible to camera shake where the outer 40% doesn't ?

Nay, because the sensor on the FF isn't turning it 35mm equivalent, where as the 1.6x crop censor is. Just as someone said earlier, what about compact slim camera with lens at 5mm, does it mean 1/5ss is going to prevent camera shake when hand held without IS?

rpstewart · 19 Sep 2008 at 17:37

Mr Jones said:
Nay, because the sensor on the FF isn't turning it 35mm equivalent, where as the 1.6x crop censor is. Just as someone said earlier, what about compact slim camera with lens at 5mm, does it mean 1/5ss is going to prevent camera shake when hand held without IS?

You can't apply the same rule of thumb to compacts simply because you don't hold them in the same way. The 1/focal length rule is based on the size, weight and ergonomics of an SLR.

D.P. · 19 Sep 2008 at 17:52

Google is full of resources. Every single page I have read indicates you have to take the crop factor into account. And analysing the physics clearly shows the crop factor is important.

Blur is proportional to the relative movement of the projected image circle across the sensor plane which is relative to the size of a sensor. 1 cm/s movement on a 500x500cm giant sensor (0.2% relative movement) would not be less than on a 0.5cmx0.5cm (200% relative movement)