EOS R7 Comparing RF lenses at similar focal lengths

[lovetoshoot2023]

Hi,

I own the R7 with the kit 18-150 lens.

I'm considering adding the 50mm 1.8 lens for portraits and landscape photography.

Will there be an appreciable difference in the image quality at 50mm between the two?

Or maybe the best comparison is at 70mm for the kit lens versus the 50mm prime.

Denny

[deebatman316]

It depends on the lens that is used. Every lens performs differently even at the same focal length. It would be best to test both lenses at the same focal length. The image sensor is causing the 1.6x crop not the lens. Lenses don't create a crop factor its the image sensor. All lenses are marked in 35mm/ Full Frame equivalent focal lengths. 

[lovetoshoot2023]

Demetrius,

Thank you for your reply. Are you still using the EF-50mm 1.8? What do you think of the results?

Denny

[deebatman316]

Yes I still have my copy of the EF 50mm F/1.8 STM lens. Actually this is my 2nd copy of it. The first one's AF motor failed and it would've cost more to repair than replacing it. This lens is focus by wire. So manual focus won't work if the AF motor was broken. The EF 50mm F/1.8 STM lens begins to be sharp at F/2.8 below that it's soft. For an RF Mount camera go with the RF Mount version instead of the EF Mount counterpart. If you're doing video work the EF version doesn't support Dual Pixel Autofocus.

[kvbarkley]

"All lenses are marked in 35mm/ Full Frame equivalent focal lengths."

Focal length is focal length. All lenses are marked with the physical focal length. It would be the same on a medium format or 4/3s format.

[Waddizzle]

“ Will there be an appreciable difference in the image quality at 50mm between the two? “

I have the full frame prime, but not the crop sensor zoom.  I would expect the prime to perform slightly better under most circumstances than the zoom, which has a fairly wide zoom ratio of 150 to 18 or 8.33:1.  My expectations should not be taken as fact!

A lot would also depend upon the shooting conditions and exposure settings.  The 50mm setpoint is close the center of the zoom range, which is where you should expect the best image quality.  

The aperture setting could also have an impact on image quality form the zoom.  I would expect the best image quality to come in at around f/8 for the zoom.  

The ISO setting should also have an impact on image quality.  The zoom may force you to use higher ISO settings than the prime.  Even so, I would expect the prime to capture better images at f/8 than the zoom.

The zoom is a pretty good walk around lens for casual shooting.  I would expect the prime to have better image quality than a high ratio zoom with a narrower aperture.  I find the RF 50mm to be amazingly sharp on the R6 mark II, although it is not my primary lens for that body.

As far as using the 50mm on an APS-C sensor body camera for portraits goes, it would work fairly well.  But it is not the path that I would be inclined to follow for portraits.  But portraits can come in many flavors from full body to head shot.

[lovetoshoot2023]

I have been taken in by the dreamy bokeh that I see in some of the advertisements for the 50mm 1.8. That said I tried some 50mm shots with the zoom and the results were quite good. That's why I'm wondering if I really have this covered already? It appears that I got f5.6 at 50mm. If that's correct than compared to the 1.8 am I getting about three time more light? The other benefit to the 50mm is that it looks unassuming in the photos and might not put someone off as easliy as a larger lens. I'm thinking of those who are already comfortable with having their photo taken with a smart phone.

Your thoughts?

[Aurora4233 · Accepted solution]

 

These are the RF50 1.8 with an R7 and for the price I couldn't be happier.  I break this lens out for portraits frequently despite having the RF24-70 f2.8.   Opening up to 1.8 with a prime is beautiful and at the price of the 1.8 it's a no brainer.

For the prices I've picked up the 16 and 28 primes as well and each has a fantastic niche despite having several zooms that cover the range already.

Again, don't lose sleep at the price of the 1.8.  You'd need a professional use agreement to justify the price, size, and weight of the 1.2 but $169 of fantastic 50mm 1.8 should have been bought yesterday 😉

[lovetoshoot2023]

Thanks for your thoughts on this and the example photos.

Denny