Question about a theoretical lens.

[Ozarker]

I'm not saying this will ever happen, but there are a lot of smart guys here who will know how to calculate this. I'm wondering what the size (front filter thread or front element?) of a 70-135 f/1.8, f/2 or 70-150mm might be, and whether or not it would be even practical from a size point of view. With what Canon has been producing lately, I am wondering whether there is a possibility that Canon would make a shorter zoom than a 70-200 f/2.8 with a wider aperture. For a guy that focuses almost exclusively on portraits, model boot camps, or fashion show runways, something faster and shorter would be really nice in a zoom, from my perspective.

 

[AlanF]

The minimum diameter for a front element for a 70-135 f/1.8 would be 75mm, at f/2 would be 67.5mm, and for 70-150mm would be 83.3mm for f/1.8 and 75mm for f/2.

 

[Ozarker]

Thank you Alan.

 

[SecureGSM]

The minimum diameter for a front element for a 70-135 f/1.8 would be 75mm, at f/2 would be 67.5mm, and for 70-150mm would be 83.3mm for f/1.8 and 75mm for f/2.

Would be around 105mm in Sigma Art money

The Sigma 50-100/1.8 Art (APS-C) thread filter
Size : 82mm

Sigma 105mm/1.4 Art (Monstrosity) - 105mm

I have got one up for sale for months and not a single punter. they all run away as soon as the lens being taken out of the box. It is a scary large 105mm prime.