There is no magical size/weight advantage

Started Mar 5, 2014 | Discussions thread
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Re: I Believe in Magic . . . ;)
In reply to razormac, Mar 5, 2014

razormac wrote:

No offense intended, but this thread is confusing at best, and not true. I am no optics expert (just an engineer with a photography habit), but these kinds of posts rub me the wrong way to the point where I have to respond.

1) Yes there is a size advantage, and no it isn't magic, just simple physics, the physics of needed less glass (and mass) to cast a smaller light circle with the same light density falling on the sensor (photos/sq cm)

Regarding the mass in terms of glass, the differences would be marginal because the front elements will be the SAME and only the rear elements will be smaller. Now, since VR is in the rear, due to the smaller rear elements, the VR mechanism will also be lighter and smaller. Other than that, the only flange back distance changes. In total mass it would be smaller, but if that is substantial or not, is a bit up to your own preferences.

2) Rather than try to argue further the physics, I will give real world examples that prove my point

Nikon 1 32mm f1.2 (2.58x1.85in) vs Nikon DX 35mm f1.8 (2.8x2.1in) - the f1.2 lens is slightly smaller than its DX equivalent despite the ~ 1 stop advantage

...and that is for the same reason as mentioned above. The 32/1.2 is a bit smaller because it is a shorter focal length, it has smaller rear elements and shorter flange back distance.

Nikon 105mm f2.8 Macro (3.3x4.6in) vs Pana 35-100mm f2.8 (2.7x3.9in) again, advantage smaller format

Apples and oranges... really. Try to make a 1:1 macro to compare with. Never the less, yes, the 105/2.8GVR is huge and heavy.

Have to cut this short as I am being called to a meeting

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