Canon RF mount has a 28-70 2.0? 2.0?!?!?!?!

[pRICE cUBE]

Chalk it up to not paying enough attention to the RF platform. I saw the announcement of the RF 24-70mm 2.8 and said to myself "the MILC version of the EF lens". I must have had the RF 28-70 2.0 pass me right by and thought they were rolling out the 24-70 again. It only occurred to me when I saw a lens listed on Craigslist as "Canon 28-70 2.0" and assumed the lister made an error. "There is no such lens".

For those who need a primer, the difference between 2.0 and 2.8 means the 2.0 allows 1 f stop more light . It would be like using ISO 1600 with 2.8 aperture but only needing ISO 800 with 2.0 aperture. You get slightly more background blur. Sounds good, right? The downside is the lens is heavier and more optical glass means more $. The RF 24-70 2.8 is 2 lb. and the 28-70 2.0 is 3 lb. of pure fun.

Now if they would make a 70-200 2.0, I would do backflips. I don't believe it is likely as the lens would needs to be quite large and probably $6,000 price tag. It would be fun though.


Canon EF 24-70mm 2.8 (left), RF 28-70 2.0 (right)

[btfc]

“ 4 times the amount of light “

Is that new math?

1.4 would be 4x; 2.0 is 2x

[vision63]

btfc wrote:
“ 4 times the amount of light “

Is that new math?

1.4 would be 4x; 2.0 is 2x

If I can't use my fingers, I can't haz math.

[pRICE cUBE]

vision63 wrote:
[quote=btfc]
“ 4 times the amount of light “

Is that new math?

1.4 would be 4x; 2.0 is 2x

If I can't use my fingers, I can't haz math.


This link explains it pretty well http://www.john-rowell.com/blog/2017/3/2...p-of-light
LIGHT IS MEASURED IN STOPS
A stop of light is not a fundamental unit, but a method of measuring the increase or decrease of light in a photographic exposure. 1 light stop is either double (+ 1-stop) or half (- 1-stop). So, irrespective of your initial exposure, increasing it by 1-stop means twice as much light, and decreasing it by 1-stop means half the amount of light. So far, so good right? Well, it gets a little more complex when you think of more than 1-stop. For example, if you increased the light by 2-stops, it is actually 4x the light (2x2), and 3-stops is 8x.

[Gareth]

Yea, you totally missed that! The 28-70mm/2L was one of the first RF lenses Canon announced. It was way more interesting than the early R cameras!

[btfc]

“ Yes, 1.4 to 2.0 is 4x less the amount of light coming in through the aperture.. ”

No, an aperture of f2.8 would let in 4x less light than an aperture of f1.4.

Check your math in the morning.

[pRICE cUBE]

btfc wrote:
“ Yes, 1.4 to 2.0 is 4x less the amount of light coming in through the aperture.. ”

No, an aperture of f2.8 would let in 4x less light than an aperture of f1.4.

Check your math in the morning.

Yeah, I seem to be crossing my wires. Went back and removed my erroneous statement.

[DP]

One of my favorite lenses for my 6D Mk. II is a Tamron 28-75 f/2.8. Not f/2 but it is a very sharp lens. My go-to lens.

I don't worry much anymore about ISO. It's amazing to me how much noise reduction, both long exposure and high ISO, has gotten so much better over just the last ten years...

[macphanatic]

DP wrote:
One of my favorite lenses for my 6D Mk. II is a Tamron 28-75 f/2.8. Not f/2 but it is a very sharp lens. My go-to lens.

I don't worry much anymore about ISO. It's amazing to me how much noise reduction, both long exposure and high ISO, has gotten so much better over just the last ten years...

I have that lens somewhere. Haven't used it in a while as I switched to Sony mirrorless. Wound up buying the Tamron 28-75 f/2.8 in E mount, which is another very good lens, especially for the money.

[deckeda]

The loss of perspective on the wide end as compared to the 24-70 is regrettable. But yeah, new mounts is where the development dollars go.