Next month, I will buy a canon EOS R5 for concert photography. I will be short on money for some months or even a whole year because of this investment.
I have a lot of EF-S lenses and some EF lenses and I'm trying to figure out if it's better to buy EOS R with RF lens (24-70 | F2.8) or EOS R5 with converter ring.

Does anyone have example photos to share with EOS R and 18-55mm or 10-18mm EF-S lens, because I saw some youtube videos about losing quality, sharpness and megapixels when using EF-S lenses on EOS R or EOS R5.

I'm currently using an EOS 800D and my EF lenses are a 50mm f/1.8 and 70-300mm f/4-5.6.

Some example photos using my Canon 800D, that i'm trying to improve with switching to mirrorless EOS R or EOS R5.

Tomi Meglic - 70-300

Canon 800D — EF 70-300mm f4-5.6 IS II @ 146mm — ISO 1600

Fans at soccer match during coronavirus

Canon 800D — EF 70-200mm F/2.8L IS III USM @ 200mm — ISO 1600
Visible noise on dark background


Canon 800D — EF 50mm F/1.8 — ISO 800

Luka Basi

Canon 800D — EF-S 18-55mm F/4-5.6 @ 55mm — ISO 3200
Visible noise on dark background

Short term is probably better to take EOS R with RF 24-70mm F2.8 (for 4500€)
Long term is probably better to take EOS R5 (for 4500€)

  • 3
    It’s not BS. When you use an EF-S lens on a full frame EOS R or R5, you lose a LOT of megapixels. You go from 45mp to 17.3mp Dec 12, 2020 at 2:15
  • 3
    What camera are you currently using and what EF lenses do you have?
    – Michael C
    Dec 12, 2020 at 3:55
  • 1
    Better yet, get an R6 and use the saved money on glass. You probably don’t need the resolution and the R6’s AF is just as good. The R’s AF is not. Dec 21, 2020 at 21:33
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    I used to do concert photography and never had more then 20 megapixels. It's fine. You only need more if you're shooting glamour or weddings. See if you can rent an R6 if you want to convince yourself. I'm going to keep my 5D MkII (also 20 megapixels) for sentimental reasons. Dec 22, 2020 at 11:54
  • 1
    If you buy an R6 and some new glass, you get more megapixels, and far better low-light performance than an R5 with adapted EF-S glass.
    – Pete
    Jan 27, 2021 at 8:54

3 Answers 3


When using an EF-S lens on any of the current EOS R series of cameras, only the center 22.5 x 15 millimeters or so will be used to contribute to the image. This is because EF-S lenses only project an image circle large enough for a sensor with a diagonal of around 27mm. That's a linear reduction by a factor of 1.6 from the dimensions of a 36 x 24 millimeter FF sensor with a diagonal of a little over 43mm. This means the area will be reduced by a factor of (1.6)², or 2.56.

Thus, the 45MP sensor of the R5 will only use the center 17.5 MP or so.

The EOS R, with a 30.4 MP sensor, will only use the center 11.88 MP or so.

So yes, when using EF-S lenses you're essentially derating your full frame body to be an APS-C crop body.

The two lenses you mention, an EF-S 18-55mm (there are nearly a dozen different versions of 18-55mm EF-S lenses) and the EF-S 10-18mm f/4.5-5.6 IS STM aren't exactly premium lenses, even for APS-C cameras. They're not terrible, but they can't hold a candle to some of the newer RF lens offerings, either.

Since you're cropping the output of the FF sensors of any of the RF bodies when using an EF-S lens, you must also multiply them by a 1.6X conversion factor to get the 35mm/FF equivalent angle of view you'll get, just as you would when using them on an APS-C camera.

  • The 18-55mm will give the same AoV as a 30-90mm FF lens would with a FF sensor.
  • The 10-18mm will give the same AoV as a 16-30mm FF lens would with a FF sensor.

Your other consideration when using these lenses for concert photography is their relatively narrow maximum apertures. Combined with the cropping required by their smaller image circle, you'll be constrained in terms of using shutter speeds as fast as you could with a FF sensor and faster primes or even f/2.8 zooms. It's really tough using a camera with a smaller sensor and a slow variable aperture zoom lens. You're being squeezed from both ends.

I tend to shoot relatively brightly lit concerts that are illuminated with theatrical style lighting using a FF body with an EF 24-70mm f/2.8 L lens and either a FF body or an APS-C body with an EF 70-200mm f/2.8 L IS II. If the stage is vibrating a lot, I might use the EF 24-105mm f/4 L IS instead of the non-stabilized 24-70/2.8. But if the light is any dimmer than that, I'm going strictly with FF bodies and prime lenses with maximum apertures like f/2, f/1.8, and even f/1.4. Usually it's an EF 35mm f/2 or EF 50mm f/1.4 plus an EF 85mm f/1.8 or EF 135mm f2 L. I'll use pretty much all of them at about f/2 or f/2.2. That's up to one stop faster than f/2.8, and three stops faster than f/5.6! This means at f/2 you can use an exposure time of, say, 1/320 where you'd need 1/40 at f/5.6 to get the same exposure at the same ISO. At f/2.8 you'd still have 1/160 available in the same light.

Compared to using an EOS R5 with those EF-S lenses, you'd probably be better off using an EOS R and spending the roughly $2,000 difference in price on a fast RF f/2.8 zoom and a couple of budget RF primes, like the RF 35mm f/1.8 IS STM an the just released RF 50mm f/1.8 IS STM or the soon-to-be released RF 85mm f/2 Macro IS STM.

When in crop mode, the R5 isn't really that much different from the 800D at high ISO.

enter image description here

The green line is the R5 when uncropped.
The Yellow line is the R5 in crop mode.
The black line is the EOS 800D.

  • I will probably still buy EOS R5 and gonna try to squeeze in also Samyang AF 14mm F2.8 RF (700 $). I would probably regret having EOS R when there is much better and updated RF beast out here.
    – Slasher
    Dec 12, 2020 at 18:01
  • 1
    @Slasher You might also regret spending almost $4K on a camera when your lenses will limit it to results you could get with lesser bodies.
    – Michael C
    Dec 12, 2020 at 23:01
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    In terms of hardware, lenses contribute more than bodies do. That is, the difference between a good lens and a "meh" lens will be far more noticeable in your results than the difference between a top tier and a "meh" camera.
    – Michael C
    Dec 12, 2020 at 23:06
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    I must chime into the lenses matter more than bodies, I have gone a much cheaper route (used 5d mark ii) but if I had taken the money for which I have bought lenses to buy a more expensive body I would have bern less happy, have you considered going with either the eos rp + nice rf or adaptered full frame ef lenses or with the eos r6 if is is important for you? If you go with the R5 consider buying some used EF primes and the adapter, a used sigma 50mm 1.4 ex and similar lenses give full frame coverage and resonable quality for not muxh money. See also used sigma 24-70 f2.8 ex dg hsm
    – lijat
    Dec 13, 2020 at 17:12
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    @Slasher You're probably expecting the R5 to be a larger difference than the 800D at high ISO than the reality is going to be. It's not much more than one stop. On the other hand, a 70-200/2.8 is one stop faster at 70mm and two stops faster at 200mm than a 70-300/4-5.6. The EF 50mm f/1.8 (series) are great values, but they're not great lenses. I doubt you'd see much difference between a 20MP sensor and a 30MP or 45MP sensor until you've stopped down to about f/5.6. The 800D is not a bad camera. $3.9K in faster lenses will get you further than a FF camera for $3.9K.
    – Michael C
    Dec 16, 2020 at 0:30

I swapped the EF-S mount on the 10-18mm STM for a metal EF mount from Ebay. It took 5 minutes to unscrew the plastic EF-S and screw on the EF metal mount. You can then use it on the 6D, 6Dii, and 5Div - everything works with no crop. The image circle covers a FF sensor from 12mm-18mm, with good coverage for video from 14-18mm. I've read that the Tamron 10-24mm VC II lens has similar coverage on FF, and it comes with a regular EF mount even though it is meant for EF-S. The example I read, the author was using the 10-24mm on an EOS R, and because it is 3rd party, the R doesn't enforce crop mode.

With the 10-18mm STM you have to be careful because the rear lens element can hit the mirror, so I never use it at wider than 14mm on my 7N or my other FF digital bodies. On my EOS R, last fall I used a manual EF->RF adapter to capture some wide angle shots. For that I used the square and the 4x3 aspect ratios to clip off the extreme edges in body. I then applied the 10-18mm lens profile to the shots in DxO, which gave surprisingly good results.

Why all this mucking around? Because I can, and because covid inspires tinkering, and because the 10-18mm is very light weight, which is nice to travel with:)

  • 2
    How is the image quality in the corners? I have a Tokina 11-16mm f/2.8 DX II, which is designed for crop frames, but has an EF mount. It covers the frame with little vignetting at 16mm. I haven't tested it thoroughly, but I've noticed quite heavy distortion of e.g., stars against the night sky, that become large crosses in the corners.
    – Pete
    Jan 27, 2021 at 8:51

Not sure if you upgraded your kit or not, but I've have several Canon bodies and depending on your need, it's always best to pick IQ over tech specs. For starters since you're a concert photographer, you need a body that will best the others in low light situations. I would ditch all of the EF-S glass if your moving to a FF body. EF lenses can be adapted to the R system w/out any loss in IQ and functionality, although, the newer RF lenses are pretty amazing. AVOID the EOS R and RP - they were basically Canon's baby steps into the mirrorless system. For the type of photography you're into, I would strongly recommend the Canon EOS R6. The money you'll save can get you a nicer RF lens - the 24-70mm RF f/2.8 would be ideal. I started with the first Rebel... I jumped to FF with the 6D and moved to the mirrorless system with the RP (I did not like that camera). It essentially was just the mirrorless version of the 6DMkII. I had the R6 for a while (and the IQ was great, but I shoot Astrophotography and the write speed was hindering my progress). I'm currently shooting with the R5 and for me, it's exactly what I needed. If you're making money on your photography, then it's worth the investment. But if not, you'll get great shots with the R6. Cheers!

  • 2
    I have upgraded to R5. Great body with an awesome performance at high ISO. R6 would be good enough and I could also buy some lenses. Now I got 16mm RF 2.8 and it's also sharp but got a lot of distortion that can be manually fixed in Lightroom.
    – Slasher
    Nov 16, 2021 at 9:13

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