IS on Prime Handheld

I mainly shoot handheld and am considering ordering the 35mm 1.4L. Coming from my 15-85mm with IS am I going to have a tough time handholding the 35mm L?

Depends on your shutter speed and your handholding ability. 1/30 or so seems ok for me on FF, but 1/50 to be safe.

I suppose with the extra speed of the lens I'll be able to keep my shutter speed where it needs to be to handhold.

No caffeine before shooting I guess.

Have you had any problems handholding your 50mm f/1.8?

It is generally agreed that you don't need IS on most fast prime lenses; at least on a FF body. Many will argue that IS will add additional weight. And if you need to use faster shutter speed that you use an external flash to compensate for the low light.

Since you're dealing with a cropped sensor, a general rule of thumb is to be able to hand hold at 1/(focal length * 1.6) to be able to not detect camera shake while hand holding. If you can hold 1/50th of second, you will be fine without IS.

???

You ESPECIALLY need IS on most fast primes - it's just that they don't have it. Fast primes are most often used in low light situations where IS is of benefit. Having IS on a lens like a 35L or 85L enables you to use a 4stop lower ISO. Or allows you to shoot in situations that is 1/16 as bright. Tell me that isn't needed. O

And flash is never ever an ideal solution for low light. There are many situations where it is not possible, or not optimal (light quality wise) to use flash.

And even when you do use flash, if you want a decently exposed photo without it looking like a cave, you will still get camera blur if your shutter is too slow

This is a scenario where in-body IS would be nice to have.

Purplecow wrote in post #13468519
It is generally agreed that you don't need IS on most fast prime lenses; at least on a FF body. Many will argue that IS will add additional weight. And if you need to use faster shutter speed that you use an external flash to compensate for the low light.

Since you're dealing with a cropped sensor, a general rule of thumb is to be able to hand hold at 1/(focal length * 1.6) to be able to not detect camera shake while hand holding. If you can hold 1/50th of second, you will be fine without IS.

Why would you multiply by 1.6? APS-C cameras do not magically make the lens reach further. Its just a different crop?

@OP: Come on, with the ISO these days in most SLR's you shouldnt need IS on a fast prime. I can hold the 85L II at low shutter speeds. If not, ill crank it up to ISO6400. If thats a no go, I can use defused flash.

lancebroad wrote in post #13470337
Why would you multiply by 1.6? APS-C cameras do not magically make the lens reach further. Its just a different crop?

@OP: Come on, with the ISO these days in most SLR's you shouldnt need IS on a fast prime. I can hold the 85L II at low shutter speeds. If not, ill crank it up to ISO6400. If thats a no go, I can use defused flash.

Getting by without IS isn't the same as it not being useful. You do need to consider the "crop factor" in determining the limits of handholding because it is exactly the same as magnifying (or cropping if you will) a shot: movement is more visible on a poster sized print than it is on a wallet sized one. The same mm of movement is seen 1.6x larger with a crop camera with an equal lens.

Its not magnified by 1.6. It doesnt get you closer. Its cropped by 1.6.

smorter wrote in post #13470231
???

You ESPECIALLY need IS on most fast primes - it's just that they don't have it. Fast primes are most often used in low light situations where IS is of benefit. Having IS on a lens like a 35L or 85L enables you to use a 4stop lower ISO. Or allows you to shoot in situations that is 1/16 as bright. Tell me that isn't needed. O

And flash is never ever an ideal solution for low light. There are many situations where it is not possible, or not optimal (light quality wise) to use flash.

And even when you do use flash, if you want a decently exposed photo without it looking like a cave, you will still get camera blur if your shutter is too slow

On a 35mm focal length, the rule of thumb is to not get camera shake, you hold 1/35 sec for your shutter speed. If you have a 4 stop IS, that means that your should be able to hand hold at 1/35 * 2 * 2 * 2, which is roughly 1/4 second. Unless you're shooting something that isn't moving, this may yield a descent result. However, if you're shooting a person, you'll pick up subject movement.

Now if you have a 200mm lens with a 4 stop IS, you can shoot at 1/15 sec without picking up camera shake.

Unless you have a 200mm 2.0L IS, your next fastest is a f2.8. This lens is two stops slower than the 35mm 1.4L.

IS makes more sense on a longer lens than a short fast lens, it really doesn't make sense. Will it help? Maybe a little but people have been shooting hand held at this focal length for a long time.

lancebroad wrote in post #13470337
Why would you multiply by 1.6? APS-C cameras do not magically make the lens reach further. Its just a different crop?

@OP: Come on, with the ISO these days in most SLR's you shouldnt need IS on a fast prime. I can hold the 85L II at low shutter speeds. If not, ill crank it up to ISO6400. If thats a no go, I can use defused flash.

The focal length of the lens doesn't change. However, the FOV does change for a cropped sensor body. For instance, if you have a 50mm lens on a cropped body, it frames the subject equivalent to that of an 80mm on a ff body. Therefore, instead of using 1/50 sec, you'll have to use 1/80 sec on a cropped body.

If this isn't clear, let's say that you have 50mm lens on both a cropped body and a ff body. To get an equivalent framing of the same subject on a cropped body, you will have to step back. This also changes the perspective. To be able to shoot from the same distance with a cropped body as a ff with a 50mm lens, you'll have to use a 31.25mm lens.

Here's another way to look at it. When the image is project to the sensor, the ratio of the image to the sensor size is bigger on a cropped body compared to that on a ff body. So a small movement on a cropped sensor is picked up more compared to that of a ff sensor. For example, if the image is moved by 1mm, that 1 mm relative to a 35mm sensor is less compared to that on a 23mm sensor.

I hope this is clear.

lancebroad wrote in post #13470489
Its not magnified by 1.6. It doesnt get you closer. Its cropped by 1.6.

And a crop is a magnification, or more precisely an enlargement. You are simply wrong on this.

lancebroad wrote in post #13470489
Its not magnified by 1.6. It doesnt get you closer. Its cropped by 1.6.

The image projected onto the sensor isn't magnified.

However, when making prints or viewing the image on the screen, you will most likely print the images from a cropped body or a ff to be the same size. This creates the magnification. Also, with the higher pixel density of an APS-C sensor, you will be able to resolve more detail which provides a zoom factor.

Some argue that with the limits of the lens, you won't be able resolve the difference.

Ugh. The image is the same as on a full frame. Its just you see less that you would on a 35mm sensor. I think you need to look into how a crop camera works. Its not bigger. Its the same, just less of it.

http://www.digital-photography-school.com/crop-factor-explained - for you. Now tell me I am worng again after reading this.

Normal lens on a FF/35mm is about 50mm
Normal lens on a APS-C is about 30mm
Normal lens on a medium format is about 80mm

A 50mm lens on an APS-C camera is considered a short telephoto for that sensor size, rough equivalent to an 80mm on a FF.