Beginner APS-C Lens on Sony a6700

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Scarq

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Hello everyone,
Yesterday I was trying to explain to my friend that APS-c lens on sony6700 will NOT have a crop factor because this particular camera already has a crop sensor. There for size of the sensor exactly fits any APS-c lens.
But my friend admits that sony6700 sensor is smaler then APS-C Lens, so it will have a crop factor. I completely disagree with that.
Can someone in details explain this.
I do understand that crop factor will appear when crop sensor camera will be mounted with Full frame lens( E mount), or Full frame camera with crop sensor lens(APS-C).
I will really apreciate as many coments as possible.

Thank you for your time.
 
You're definitely wrong and your friend may be too. The problem is using the term 'crop-factor' as it's misleading. An APS-C lens simply has a smaller image circle than a full-frame lens of the same focal length but the image on the sensor will be identical. The focal length doesn't magically change just because you put the lens on a different body. What does change is the angle of view so a 50mm lens on an APS-C camera will give the same angle of view as a 75mm lens on a full-frame camera but it is still a 50mm lens.

Finally, what is a Sony 6700? There's no such camera that I'm aware of so the bit about its sensor size simply doesn't make sense.
 
Further to @Snapsh0t advice all lenses attached to an APS-c camera will all be affected by the angle of view. If you put on a full frame 24-70 lens on a crop camera (1.5x for Sony A6xxx series) then the angle of view equivalence becomes 36-105mm. If it was a crop camera specific 24-70 lens it would still give 36-105. Usually a crop camera lens that tries to be the equivalent of a full frame 24-70mm lens will actually be a different focal range something like 17-55 (ie angle of view 25.5mm to 82.5mm). This is because the lens focal range markings on a lens are the same. It doesn’t matter if it’s a crop or full frame lens. It’s whether it’s attached to a crop camera whether the angle of view is different.

I did a little test a few years back. 300mm lens on a full frame camera, 70-200 lens on a crop camera (although in my haste I knocked the zoom back to 185mm).

D71_8459 by -Rob - Nikon-

DSC_9172 by -Rob - Nikon-

The framing was roughly the same but the background property due to the perspective of lens focal length and the smoothness of the depth of field on a full frame sensor that makes a difference.
 
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Scarq said:
Hello everyone,
Yesterday I was trying to explain to my friend that APS-c lens on sony6700 will NOT have a crop factor because this particular camera already has a crop sensor. There for size of the sensor exactly fits any APS-c lens.
But my friend admits that sony6700 sensor is smaler then APS-C Lens, so it will have a crop factor. I completely disagree with that.
Can someone in details explain this.
I do understand that crop factor will appear when crop sensor camera will be mounted with Full frame lens( E mount), or Full frame camera with crop sensor lens(APS-C).
I will really apreciate as many coments as possible.

Thank you for your time.
Click to expand...

This often leads to so much contention and pedantic argument, so be prepared :D

By crop factor people usually mean with reference to Full Frame (35mm equivalent.) The Sony A6700 is an APS-C camera and x 1.5 crop. This is the same as most other APS-C cameras except Canon which use a slightly smaller APS-C format which is x 1.6 crop. So, for example, a 50mm lens when mounted on the A6700 will look like the FF equivalent of 75mm.

I hope that helps.
 
Snapsh0t said:
You're definitely wrong and your friend may be too. The problem is using the term 'crop-factor' as it's misleading. An APS-C lens simply has a smaller image circle than a full-frame lens of the same focal length but the image on the sensor will be identical. The focal length doesn't magically change just because you put the lens on a different body. What does change is the angle of view so a 50mm lens on an APS-C camera will give the same angle of view as a 75mm lens on a full-frame camera but it is still a 50mm lens.

Finally, what is a Sony 6700? There's no such camera that I'm aware of so the bit about its sensor size simply doesn't make sense.
Click to expand...


Yes there is -
http://thenewcamera.com/tag/sony-a6700/
 
f/2.8 said:
No, there isn't. There was a rumoured release of a camera called the A6700, when it was actually released though it was called the A6600.

There is no A6700 it doesn't exist.

The o.p must have got his model numbers mixed up.
Click to expand...

Fair shout buddy- I just googled it lol
 
Am I right in saying the focal length marked in mm on a lens is of the 35mm equivalent whether the lens is a full frame or crop lens? ie both a 70-300 full frame lens and a 70-300 crop lens would give exactly the same field of view on a crop body. It’s just a full frame lens works on both crop and full frame cameras whilst a crop lens only works on a crop camera (on full frame the camera uses either crop mode or image will have a vignette).
 
Maybe it should be thought of the other way round. If you put a 50mm lens designed for an aps-c camera onto FF camera (not recommended) the field of view would be the same, but no doubt with pretty bad vignetting. In a way it's the sensor size, not the lens that determines the field of view (although they work in conjunction with each other).
 
rob-nikon said:
Am I right in saying the focal length marked in mm on a lens is of the 35mm equivalent whether the lens is a full frame or crop lens? ie both a 70-300 full frame lens and a 70-300 crop lens would give exactly the same field of view on a crop body. It’s just a full frame lens works on both crop and full frame cameras whilst a crop lens only works on a crop camera (on full frame the camera uses either crop mode or image will have a vignette).
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Yes and no. Mostly yes, but your first assertion is not quite right.

The focal length marked on the lens is a physical property of the lens, and it has that property regardless of whether or not it's attached to a camera. So a 70-300mm lens is a 70-300mm lens, no need for it to be "equivalent" to anything.

It follows that a 70-300mm lens designed (with a large image circle) for a full frame sensor has the same focal length as a 70-300mm lens designed (with a small image circle) for a crop sensor. In both cases the focal length is 70-300mm. And therefore, when you mount them on a crop sensor body, they will both display exactly the same image.

Of course the image you get when you mount those two lenses on a crop sensor camera has a narrower field of view than you would have if you mounted the full frame sensor on a full frame camera, and that's where the notion of equivalence and crop factors comes into play.
 
StewartR said:
Yes and no. Mostly yes, but your first assertion is not quite right.

The focal length marked on the lens is a physical property of the lens, and it has that property regardless of whether or not it's attached to a camera. So a 70-300mm lens is a 70-300mm lens, no need for it to be "equivalent" to anything.

It follows that a 70-300mm lens designed (with a large image circle) for a full frame sensor has the same focal length as a 70-300mm lens designed (with a small image circle) for a crop sensor. In both cases the focal length is 70-300mm. And therefore, when you mount them on a crop sensor body, they will both display exactly the same image.

Of course the image you get when you mount those two lenses on a crop sensor camera has a narrower field of view than you would have if you mounted the full frame sensor on a full frame camera, and that's where the notion of equivalence and crop factors comes into play.
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Great explanation there (y)
 
Thank you for all your comments people. This topic opened a new field of information for me. I'm a bit more puzzled now with this mythical "crop factor"... Im the owner of a full frame camera now, so there is no need for me to go even more deeper it this topic.
 
Scarq said:
Thank you for all your comments people. This topic opened a new field of information for me. I'm a bit more puzzled now with this mythical "crop factor"... Im the owner of a full frame camera now, so there is no need for me to go even more deeper it this topic.
Click to expand...
It's basically the difference between the angle of view of a given focal length on the smaller sensor compared with full frame/35mm film. So a 50mm lens used on APS-C gives the same angle of view as a 75mm lens used on full-frame. 75 / 50 = 1.5. I think the term originated in how much one would have to crop the full-frame image to get the effect of the lens when used on a smaller format.
 
Scarq said:
Thank you for all your comments people. This topic opened a new field of information for me. I'm a bit more puzzled now with this mythical "crop factor"... Im the owner of a full frame camera now, so there is no need for me to go even more deeper it this topic.
Click to expand...
Actually there is no need to go in to this subject for apsc shooters either. Unless you shoot multiple formats you should just know which is wide, nomal and tele views.
 
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