topic Re: EF vs EF-S interchangeability in EF & RF Lenses

EF vs EF-S interchangeability

privateaddressf — Tue, 02 May 2023 16:22:35 GMT

I know this has been discussed before, but I have a fairly specific case and I'm still not sure how the discussions apply. My wife has agreed to photograph a relative's wedding. She has done some semi-pro photography before but her Sony alpha DSLR has been acting up and she is buying an m50 as a backup. She needs to buy lenses quickly.

If she buys an EF 50mm and an ef-s 50mm and takes a picture from the m50 (aps-c) with each lens, in the same place, will the two pictures produced by the camera subtend the same visual angle or will one of them portray a larger apparent visual angle?

We don't have time to experiment with lots of things and do three or four rounds of shipping to get the fovs she needs covered. It would also be nice not to waste money on redundant lenses if EF and EF-S focal ranges behave differently when used on her camera.

Re: EF vs EF-S interchangeability

AtticusLake — Tue, 02 May 2023 16:49:57 GMT

They're both 50mm lenses, so they should give you the same exact picture. (In practice, 50mm is kind of approximate, so the pictures may vary slightly.)

The difference between those lenses is the size of the image they produce; i.e. the size of sensor they cover. But they will both cover the APS-C sensor in that camera. You will need an adapter, of couse, since the camera's lens mount is EF-M.

If you later used these lenses on a full-frame RF camera, like the R5, then the EF-S lens would put the camera into crop mode, giving you a narrower view. You can not use the EF-S lens on an EF camera.

If you want more info on lens mounts and compatibility, here's an article I wrote: https://moonblink.info/MudLake/gear/lenses

Re: EF vs EF-S interchangeability

privateaddressf — Tue, 02 May 2023 16:56:19 GMT

So to confirm, buying a 50mm EF lens and an 85mm EF-S lens will produce significantly different images? Not the difference between an 80mm and an 85mm both from EF-s lenses that the crop factor camp would suggest? Remember, someone's wedding photos are on the line here.

Re: EF vs EF-S interchangeability

rs-eos — Tue, 02 May 2023 17:16:34 GMT

A 50mm focal length is a 50mm focal length. So any of the characteristics, distortions, etc. of that lens would still mainly be there no matter the camera it's used on.

e.g. a 50mm focal length on full-frame for headshots will lead to facial distortions (typically the person's nose and any feature closest to the camera will be exaggerated). On a crop-sensor body, while the field-of-view of the 50mm will be as an 80mm lens on a full-frame camera, those distortions will still be there. Though due to framing of the headshot, you'd be physically further back, so the distortions may be lessened.

If you're comparing 50mm vs 85mm on a crop-sensor (or on full-frame), they would indeed be different. Though I wouldn't say drastically different. The 85mm would render portraits betters (less facial distortions with headshots) and give you a narrower field-of-view vs the 50mm.

Re: EF vs EF-S interchangeability

AtticusLake — Tue, 02 May 2023 17:19:01 GMT

If you're asking me to take responsibility for someone's wedding photos, then no, you have to pay for that kind of support. Please try to remember how much you're paying for this information. I'm just giving you the best of my understanding on a best-guess basis.

If you're shooting something that has a major impact, like a wedding, and particularly for money, it's your resposibility to know your gear, and know how to use it. Please dont try to fob that off onto online forums. That's a sure road to disaster. If your wife isn't confident enough to kow how to figure this out, then she shouldn't take the job.

But based on my best-guess, top-of-the-head, just-what-I-think-I-remember wild-assed guess, yes. The focal lengths are different, so the angles of view will be different, as different as the numbers imply. There's no reason an APS-C camera would do anything different with those 2 lenses. At least no reason I can think of offhand.

Not the difference between an 80mm and an 85mm both from EF-s lenses that the crop factor camp would suggest?

No idea what that means.

Re: EF vs EF-S interchangeability

privateaddressf — Tue, 02 May 2023 18:18:16 GMT

The wedding shoot is being done as a favor, free of charge, but it's still someone's wedding. All I'm saying is there is definitely conflicting information around and this isn't a hypothetical or I'm thinking of buying something someday, so if you're not sure, just say you're not sure. I'll see if I can find technical drawings/specifications to confirm this, but if this forum is confident the fov presented in the picture when using the two lenses will be the same, then we can shop that way and I'll let you know if you were right later.

This is the same problem we had when my wife was moving from a Minolta to a Sony alpha. The lenses were compatible in terms of mounts, but a 50mm Minolta lens used on the alpha yielded the same fov as an 80mm Sony lens used on the same camera. Because the alpha had an aps-c sensor, the sensor only picked up some of the resolved image from the lens, meaning the picture subtended a smaller visual angle. If Canon has somehow fixed this problem when moving between EF and EF-S, (or in the adapter from EF/EF-S to EF-M) then that's awesome.

Re: EF vs EF-S interchangeability

deebatman316 — Tue, 02 May 2023 19:11:52 GMT

What you're describing is not a problem. It's the image sensor that makes the image more narrow. Since the image sensor is smaller than full frame (36x24). It only can record the center of a full frame lens. A 50mm lens used on a Sony camera would yield an angle of view of 75mm instead of 80mm. Since Sony's and everyone else's APS-C crop factor is 1.5x opposed to 1.6x that Canon uses.

Re: EF vs EF-S interchangeability

privateaddressf — Tue, 02 May 2023 20:52:49 GMT

Ok, thanks to everyone for the help. Sorry for the panic. To be clear, the narrowed field of view isn't a problem per say. I just need to make sure she doesn't do something like buy an EF 50mm and an EF-S/EF-M 85mm since those would end up being basically the same field of view and leave her unable to take shots closer up. She just needs to make sure she can cover her distance bases since she won't always be able to move wherever she needs to to get "the right shot".

Again, thanks for everyone's help

Re: EF vs EF-S interchangeability

MikeSowsun — Tue, 02 May 2023 21:58:02 GMT

No, You still have it wrong…..

An EF 50mm and an EF-S/EF-M 85mm will NOT produce similar field of view. Not even close.
Neither will an EF 85mm and an EF-S/EF-M 50mm. If she buys an EF 50mm and an ef-s 50mm, they will both look the same when used on the same camera.

Re: EF vs EF-S interchangeability

deebatman316 — Tue, 02 May 2023 22:00:01 GMT

Almost all of Canon's prime lenses are full frame (EF) not EF-S. Except for the EF-S 24mm lens. So a 50mm on crop sensor camera would have an equivalent angle of view of 80mm when compared to full frame. Then an 85mm lens would have an equivalent angle of view of 136mm when compared to full frame. It's the image sensor that causes the crop NOT the lens. An EF 24mm lens & EF-S 24mm lens would yield the same result. Crop factor applies to all lenses wether Full Frame or APS-C. This is due to the image sensor NOT the lens. You can easily see this while looking through the viewfinder on an APS-C camera. Try with a 50mm lens 85mm lens. They will look drastically different.

Re: EF vs EF-S interchangeability

johnrmoyer — Tue, 02 May 2023 21:40:39 GMT

https://www.cambridgeincolour.com/tutorials/digital-camera-sensor-size.htm

This article aims to address the question: how does your digital camera's sensor size influence different types of photography? Your choice of sensor size is analogous to choosing between 35 mm, medium format and large format film cameras — with a few notable differences unique to digital technology. Much confusion often arises on this topic because there are both so many different size options, and so many trade-offs relating to depth of field, image noise, diffraction, cost and size/weight.

Background reading on this topic can be found in the tutorial on digital camera sensors.

Re: EF vs EF-S interchangeability

krahe — Tue, 02 May 2023 21:52:22 GMT

The short answer is that on a crop sensor camera like the M50, a longer focal length will yield a narrower FOV than a shorter focal length, regardless of whether the lens was designed for a full frame camera or what the FOV would be on such a camera with the same lens.

Re: EF vs EF-S interchangeability

Tronhard — Fri, 28 Jul 2023 06:02:07 GMT

Read this:
As has been said, a 50mm lens is a 50mm lens, no matter the mount: EF or EF-S. What makes the difference is what the sensor can capture from what the lens projects into the camera. For a full explanation see:
Equivalence.pdf

Re: EF vs EF-S interchangeability

privateaddressf — Wed, 03 May 2023 05:05:32 GMT

Ok, let's see if I've got this now after trying to digest all that.

The fov is a function of two things. Sensor size, and lens focal length. Swapping lenses of equal focal length on the same camera always produces the same fov.

Changing sensor sizes with a set focal length (e.g. 50mm on a full frame vs 50mm on an aps-c) changes the captured fov.

The "crop factor" then is really an effect of moving to a different sensor size. A photographer used to using a 50mm lens for a particular setting with a full frame camera will have to adjust which lens/focal length they use in that setting if they switch to a smaller sensor?

Re: EF vs EF-S interchangeability

Tronhard — Wed, 03 May 2023 06:21:29 GMT

That is true as far as it goes. Certainly a 50mm EF lens has the same focal length as an EF-S lens. However, on a crop-sensor camera, while the lens has the same Angle of View that is what it projects towards the sensor, the sensor captures a smaller area of that (Field of View), which is equivalent to using a lens of a longer focal length on a FF body - hence the term Equivalence. To go back to the original post, given a Sony Alpha has approximately the same size as a Canon APS-C camera, so the Fields of View, assuming the same or similar lenses, should be about the same.

Re: EF vs EF-S interchangeability

johnrmoyer — Wed, 03 May 2023 10:27:10 GMT

@privateaddressf wrote:
Ok, let's see if I've got this now after trying to digest all that.
The fov is a function of two things. Sensor size, and lens focal length. Swapping lenses of equal focal length on the same camera always produces the same fov.
Changing sensor sizes with a set focal length (e.g. 50mm on a full frame vs 50mm on an aps-c) changes the captured fov.
The "crop factor" then is really an effect of moving to a different sensor size. A photographer used to using a 50mm lens for a particular setting with a full frame camera will have to adjust which lens/focal length they use in that setting if they switch to a smaller sensor?

Yes

Re: EF vs EF-S interchangeability

ebiggs1 — Wed, 03 May 2023 14:53:15 GMT

Beyond the FOV issue, I will suggest she not buy or use a 50mm lens on a cropper for a wedding. I have done more weddings than I can count and the times I used a 50mil could be counted on the fingers of one hand. Its just not a very useful FL.

I don't believe you mentioned what camera she has or what lenses she has. If she has one of the Rebels with the standard, 18-55mm, kit lens she has what she needs. My main most second lens is the 70-200mm as sometime you just can't get up close to the action. Some of the churches limited me to the very back of the church. Even beyond that grabbing a shot of the actual ceremony with out being right up in front and personal has its blessings. My goto combo is the ef 24-70mm f2.8L and ef 70-200mm f2.8L. Used more than 90% of the time. A similar combo for a cropper like a Rebel is the mentioned 18-55mm and the ef-s 55-250mm.

Not shot with a 50mm nor was the one below.

The big take away from all this is look through the camera's view finder as no matter what camera you have that is what you will get. If you are unfamiliar with the wedding venue make a visit and check it out. Take a willing stand-in subject with you.

Canon 1DX with ef 24-70mm lens. ISO 200, SS 1/250, f8.

Re: EF vs EF-S interchangeability

privateaddressf — Wed, 03 May 2023 18:24:21 GMT

My wife had been shooting with an old Sony alpha 500 but hasn't done much for a while. I managed to convince her not to dabble in the professional world for now because she can't keep from getting the images perfect in Photoshop after the shoot which means her pay per hour wouldn't really be worth her time.

The new camera will be an m50 II.

She's done enough volunteer portraits, weddings as a backup photographer, family shoots, livestock, landscape etc. that she knows what she wants. At least she knows what she uses on the Sony for different shots, its just a matter of figuring out what lenses will provide the same effects on the Canon. She was under the impression that lenses made for smaller sensors compensated for the sensor size so the length needed to be adjusted when buying older full frame lenses, but after all the great help here I was able to draw the optics diagrams to help her understand how it works (which of course contradicts all the info she got from online people who don't understand this stuff like you guys do.)

Re: EF vs EF-S interchangeability

ebiggs1 — Thu, 04 May 2023 14:46:43 GMT

My personal recommendation for her would be the Rebel T8i with the standard kit 17-55mm lens and add the 55-250mm lens. I am not and have never been a fan of the, or any, M series cameras. The sheer amount of Canon lenses and other accessories dwarfs what is available for the M series.

Re: EF vs EF-S interchangeability

krahe — Thu, 04 May 2023 15:24:21 GMT

I can't say anything about accessories, but as far as lenses go there are actually far more available for an M series camera if you include those that can be used with an adapter than there are for a T8i.