# RF Trinity Len Sizes?



## felipeolveram (May 29, 2019)

Anyone who has been to these photo shows can you confirm the size of the trinity RF Lenses? Are they the same size as their EF Counterparts? I tried putting a 24-70mm and 16-35mm on a EOS R and with the adapter the size is just huge. Hoping that the RF Lenses will be the same size or less so it would balance more with the need of an adapter. I can't tell from images of videos of what the size (length/width/diameter) of them are. Will the 15-35mm, 24-70mm, and 70-200 be interal zoom or external zoom? 

This website has the patent and varying lens lengths. https://www.canonrumors.com/patent-lots-of-optical-formula-lens-patents-for-the-rf-mount/

This is a quote taken from the length of the 15-35mm. There are three sizes what do they mean?


> Whole length of the lens 135.05mm 125.84mm 125.33mm


What do the different numbers mean?


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## Mt Spokane Photography (May 29, 2019)

I have my EF 24-70 II sitting on my R right next to me. Its about the same as my 5D MK IV in size, when you figure the thicker body of the mark IV. The balance of the RF should be better, but weight will be close.

Right now, the EF lenses are my choice since they can be used with either camera.


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## Maximilian (May 29, 2019)

Hi felipeolveram!



felipeolveram said:


> ...
> There are three sizes what do they mean?
> ...
> What do the different numbers mean?





> Focal distance 15.30mm 24.20mm 34.00mm
> Whole length of the lens 135.05mm 125.84mm 125.33mm


The "whole length of the lens" is the lengh of the optical formula from the front/first lens element to the image plane on the sensor.
To get an impression of the mechanical length of the lens barrel or tube you have to subtract the flange distance (RF: 20 mm, EF: 44 mm).
Zoom lens patents are displayed at minimum, middle and maximum focal length/distance.
So at 15 mm the lens extracts to 115 mm (=135-20) while at 24 and 34 mm the lens is about 105 mm long.

Now you can compare to the technical data of EF lenses.

Hope, I could give you a clue.


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## felipeolveram (May 29, 2019)

Maximilian said:


> Hi felipeolveram!
> 
> 
> 
> ...



So that is not referring to whether or not the lens barrel will extend outward like the 24-105 or 24-70? What would be the overall external length of the lens?


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## Maximilian (May 29, 2019)

felipeolveram said:


> So that is not referring to whether or not the lens barrel will extend outward like the 24-105 or 24-70? What would be the overall external length of the lens?


It is. 

Internal zoom lenses like the EF 70-200L/2.8 have a constant "whole length of the lens".

The quoted patent for a RF 15-35 has a length that is differing by at least 1 cm (115mm-105mm).
So the lens will be about 105 mm long when retracted and about 115mm when extracted. 
Even if this 1 cm difference is small I don't see reason or possibility to keep the barrel at a constant length.


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## neuroanatomist (May 29, 2019)

Maximilian said:


> Even if this 1 cm difference is small I don't see reason or possibility to keep the barrel at a constant length.


Current UWA zoom lenses have an inner barrel that moves short distances as the lens is zoomed (<1 cm, depending on the lens), with the outer barrel providing the filter/hood attachment and giving a fixed length for the physical lens. That inner barrel is the reason Canon states that for weather-sealed UWA L lenses, a front filter is required to complete the sealing (same for the 50/1.2L lenses, both EF and RF, and the RF50 inner barrel retracts quite a ways into the lens when focused at infinity).

So, I would expect the RF UWA lenses to be fixed length with a moving inner barrel.


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## Maximilian (May 30, 2019)

neuroanatomist said:


> Current UWA zoom lenses have an inner barrel
> ...
> So, I would expect the RF UWA lenses to be fixed length with a moving inner barrel.


Thanks for that explaination. 
I wasn't aware that this would be called "fixed length" or even "internal zoom". 

So then the RF 15-35 would/could have a constant barrel with about 115 mm length.


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