Advice: The benefits of Full Frame?

[Bear]

This is a request for advice
...

After reading the thread, my suggestion would be to keep your T3i until you run in to its limitations and spend your money buying high quality lenses that you need for whatever you are photographing. Make sure the new lenses will work on a FF camera as well if that is where you want to head eventually.

I know the phrase "run into its limitations" is a bit nebulous, and you will have to decide if/when you've run into them. As for lenses, if you buy lenses first, you can buy a FF body and have most of the lenses you need. If you bought a FF camera now, you would also have to get a couple of lenses right away.

My current D-SLR is 7.5 years old now (Nikon D200) and working fine. I feel no need to upgrade to a newer camera. I do feel yet another lens would be a bigger help.

 

[OreoCookie]

I've just bought the 6D and the viewfinder size is a huge plus.

You're right about the viewfinder, I forgot about that.

I've yet to take that many photos with it - is full frame really sharper than crop?

As a general rule, neither is sharper than the other, you really have to look at lens/sensor combos to say something. These days, crop and full frame cameras have comparable pixel count (unless you spring for a D800) which means full frame cameras have lower pixel density. That makes it easier for the optical system, because its resolution can be lower. The sensor is bigger and it is much harder to build lenses that resolve the corners of a full frame sensor. On the other hand, APS-C-sized sensors have the sweet spot advantage, i. e. they see »less« of the corners where the image quality tends to deteriorate.

If you couple a quality lens to a good sensor, then you'll have great image quality. Also, lenses retain their values, so you should not buy lenses, pretending you already own a full frame body. Lenses also last much, much longer than bodies, my best lens is ~20 years old.

The other thing people forget about full frame cameras is size: equivalent lenses are much, much bigger. If I were you, I'd consider Fuji's X system. Although whether a rangefinder-style camera fits your photographic needs better than a dslr depends on what and how you shoot.

 

[AT06]

You're right about the viewfinder, I forgot about that.

As a general rule, neither is sharper than the other, you really have to look at lens/sensor combos to say something. These days, crop and full frame cameras have comparable pixel count (unless you spring for a D800) which means full frame cameras have lower pixel density. That makes it easier for the optical system, because its resolution can be lower. The sensor is bigger and it is much harder to build lenses that resolve the corners of a full frame sensor. On the other hand, APS-C-sized sensors have the sweet spot advantage, i. e. they see »less« of the corners where the image quality tends to deteriorate.

If you couple a quality lens to a good sensor, then you'll have great image quality. Also, lenses retain their values, so you should not buy lenses, pretending you already own a full frame body. Lenses also last much, much longer than bodies, my best lens is ~20 years old.

The other thing people forget about full frame cameras is size: equivalent lenses are much, much bigger. If I were you, I'd consider Fuji's X system. Although whether a rangefinder-style camera fits your photographic needs better than a dslr depends on what and how you shoot.

Thanks. I have a 24-105mm L lens at the moment which stays on 99% of the time. Definitely noticed a quality bump from my now (very) old 400D.

 

[Puckman]

After reading the thread, my suggestion would be to keep your T3i until you run in to its limitations and spend your money buying high quality lenses that you need for whatever you are photographing. Make sure the new lenses will work on a FF camera as well if that is where you want to head eventually.

I know the phrase "run into its limitations" is a bit nebulous, and you will have to decide if/when you've run into them. As for lenses, if you buy lenses first, you can buy a FF body and have most of the lenses you need. If you bought a FF camera now, you would also have to get a couple of lenses right away.

My current D-SLR is 7.5 years old now (Nikon D200) and working fine. I feel no need to upgrade to a newer camera. I do feel yet another lens would be a bigger help.

This is probably the direction I will end up going. Perhaps at this stage, it's hard to justify a new body (FF or not) and I need to spend more time getting better at just taking photos with what I have, and spend whatever money I want to spend on better lenses (that will eventually still work on a FF body if need be).

Again, thanks all for the input!

 

[Policar]

Fwiw, I'm strongly considering going back to APS-C from FF. I can't afford the lenses I want on FF (24-70mm II; 135mm f2; 200mm f2 IS), but more importantly I almost never take photos anymore.

I tried buying a 45mm TS-E to replace my 4x5 rig with my 5D III, but the image quality and flexibility are garbage by comparison, and if I'm going to shoot six photos a year they might as well be 4x5.

The real advantage of FF is that you get a stop and a third shallower DoF and low light. The 50mm f1.8 and 50mm f1.4 lenses are magic on FF; the 70-200mm zoom is amazing, too. But unless you're printing really big or want that specific shallow focus high acutance look, I can't see how you'd notice the difference.

The big viewfinder (and amazing AF, on the 5D mark III, at least) are nice. But unless you identify something you specifically want or a lens of which you specifically want to maximize the potential, I can't see your images improving at all.

Also this new Sigma 18-35mm f1.8 is pretty nice and cheap... And that Tokina 11-16mm (and the Canon 10-22mm) are pretty nice, too.

 

[OreoCookie]

Ditto, I could have gotten a used D700 instead of getting the X100s, but honestly, I made a good choice. I find a rangefinder-style camera much more appealing and suitable for my needs. I honestly don't think I have used my dslr once after getting the X100s. And the image quality is so good that I don't need a full frame sensor. (Although I wish, I had the shallower depth of field.)

 

[Ish]

Fwiw, I'm strongly considering going back to APS-C from FF. I can't afford the lenses I want on FF (24-70mm II; 135mm f2; 200mm f2 IS), but more importantly I almost never take photos anymore.

I tried buying a 45mm TS-E to replace my 4x5 rig with my 5D III, but the image quality and flexibility are garbage by comparison, and if I'm going to shoot six photos a year they might as well be 4x5.

The real advantage of FF is that you get a stop and a third shallower DoF and low light. The 50mm f1.8 and 50mm f1.4 lenses are magic on FF; the 70-200mm zoom is amazing, too. But unless you're printing really big or want that specific shallow focus high acutance look, I can't see how you'd notice the difference.

The big viewfinder (and amazing AF, on the 5D mark III, at least) are nice. But unless you identify something you specifically want or a lens of which you specifically want to maximize the potential, I can't see your images improving at all.

Also this new Sigma 18-35mm f1.8 is pretty nice and cheap... And that Tokina 11-16mm (and the Canon 10-22mm) are pretty nice, too.

You ought to ask yourself why you almost never take photos any more. Given you've added a to the comment makes it look as though it's not a situation you're happy with. If it's not that you're just no longer interested, might it be the weight of your gear that's holding you back?

What sort of photos do you enjoy taking? If you go on treks to take landscape photos like Phrasiklea does, you can certainly make the most of the 5DIII, but do your photos benefit from this?

I upgraded my camera a few times and ended up with a Canon 5DII with a 24-105L lens plus a wonderful 100mm macro. Very useful when I was shooting for large backdrops but my personal photography fell by the wayside. If you enjoy street photography for example, the 5DIII isn't exactly something you pull out of your pocket. I had a small camera which did fit in my pocket but I wasn't that impressed with the quality.

It might be worth researching the new APS-C mirrorless cameras. That's the road I investigated. The Sony NEX and the Fuji X are the two major ones that come to mind but there are probably more. I prefer the quality of the Fuji X cameras over the NEX but now there are more third party lenses for the latter the quality should be better. Like OreoCookie, Fuji X is the way I went too, only with an interchangeable lens model. There are a number of good quality lenses available for them now and more to come. The price of them isn't bad either. At last there are cameras that will give me quality with light weight! It may be the same with the NEX forums, but the Fuji X ones have loads of people who have rediscovered the joy of photography, and an extra 1/2" in height(!) now they don't have to be weighed down.

If none of this applies to you, then please ignore. Just hoped I might help if you were in the same situation I was.

I'm going on holiday in a couple of days. I'm just taking the Fuji with me and can't wait to take photos! I feel as though I've got some of the old excitement back.

Want to buy a 5DII anyone?

 

[Policar]

I upgraded my camera a few times and ended up with a Canon 5DII with a 24-105L lens plus a wonderful 100mm macro. Very useful when I was shooting for large backdrops but my personal photography fell by the wayside. If you enjoy street photography for example, the 5DIII isn't exactly something you pull out of your pocket. I had a small camera which did fit in my pocket but I wasn't that impressed with the quality.

It might be worth researching the new APS-C mirrorless cameras. That's the road I investigated. The Sony NEX and the Fuji X are the two major ones that come to mind but there are probably more. I prefer the quality of the Fuji X cameras over the NEX but now there are more third party lenses for the latter the quality should be better. Like OreoCookie, Fuji X is the way I went too, only with an interchangeable lens model. There are a number of good quality lenses available for them now and more to come. The price of them isn't bad either. At last there are cameras that will give me quality with light weight! It may be the same with the NEX forums, but the Fuji X ones have loads of people who have rediscovered the joy of photography, and an extra 1/2" in height(!) now they don't have to be weighed down.

I mostly take snapshots on vacation or during time off, which explains a lot of this… Today is my first day off from work in nine months, not counting weekends (which are usually just a day, anyway). Just too busy!

I try to take a few landscape pictures a year, but I don't live in a terribly photogenic location. If I only take two or three pictures I like per year, they might as well be on the view camera, although it's so obnoxious using that thing and I'm bad at exposure and focus. Really makes me feel incompetent in a lot of respects trying to wrangle with large format. But I bought a very nice Horseman 6x12 back so I can shoot Velvia 50 again (which was very unfortunately discontinued on 4x5 in favor of the significantly worse Velvia 100 emulsion) and that makes bracketing easy and affordable (and scans on the Nikon 9000 feasible), really making the process a lot cheaper if you're not mortified by the 2x1 aspect ratio and the obvious loss of negative size in one axis. And the Nikon produces ok scans... at 155 megapixels!

My other hobby is video, and my video kit is APS-C Canon (for which I have the 11-16mm Tokina, 17-55mm f2.8 Canon, 18-35mm f1.8 Sigma, etc. as APS-C only lenses), so I feel like my next still camera should be APS-C Canon so I can share all the lenses. The X100S would be my choice otherwise, and I do have an EOS-M, which I love in some respects (it's sharper than the 7D by a significant amount and the 22mm f2 lens is GREAT and has a wonderful FOV) but the autofocus is so exceptionally bad and ergonomics are terrible with big lenses.

I might have to lose both that and the 5D Mark III and just go with a 70D, which seems like a decent camera for video, too, as a back up for the C100.

Congrats on the Fuji, though. That seems like an amazing camera.

Fwiw, I agree the 100mm f2.8 macro is amazing and a great reason to shoot FF, but the 24-105mm f4, as wonderful a lens as it is, seems odd to me. You have a huge camera then that's not particularly good at anything. The f4 aperture really negates the point of FF; at that point it's like a huge point and shoot with a great viewfinder. But I do think it's a nice lens all the same.

 

[ChrisA]

...
I've been considering an "upgrade" to a FF (more specifically the 6D, which I have read great things about). I know some (but not all) of my lenses will work just fine on the 6D, and am willing to sell and replace the ones who don't.
...

1) The biggest question is how are you images displayed? Do you make large size prints (bigger than 8x10, maybe 24" wide or larger) or do you only look at them in an electronic screen? All screen have such poor resolution that yu don't see much if any improvement in quality, the screen itself is the bottleneck.

2) Why go to "only" FF? If you'd like to change formats and you shoot landscapes why pick a 36mm x 24 mm frame size? Traditionally people used 36x24mm because that was all they could afford. But now 36x24mm has becaome one of the most expensive formats. Have you considered other sizes and do you have a good reason not to use them?

You caould buy an entire used Hasselblad system for the price of a Canon 6D body. And obviously the Hasselblad would just blow the 6D ouot of the water in terms of image quality

Why not shoot 4x5? Seriously. Don't say if costs to much not if you can afford a FF dSLR. 4x5 is cheaper Keep the Canon and buy a large format. That will make a HUGE difference in your work. But NO ONE BUT YOU will see any difference if you move to a FF Canon, the difference is to subtle to notice for most people. The 4x5 is way cheaper and will outperform even the Hasselblad.

I'd say keep the APS-C sized Canon for it's portability and if you want better quality images make the jump away fro small format altogether.

----------

After reading the thread, my suggestion would be to keep your T3i until you run in to its limitations and spend your money buying high quality lenses that you need for whatever you are photographing. Make sure the new lenses will work on a FF camera as well if that is where you want to head eventually.

I know the phrase "run into its limitations" is a bit nebulous, and you will have to decide if/when you've run into them. As for lenses, if you buy lenses first, you can buy a FF body and have most of the lenses you need. If you bought a FF camera now, you would also have to get a couple of lenses right away.

My current D-SLR is 7.5 years old now (Nikon D200) and working fine. I feel no need to upgrade to a newer camera. I do feel yet another lens would be a bigger help.

I have the same D200. As long is the final output medium is an electronic screen, I expect I will never run into any limitations. That said, Eventually I will want to upgrade my VIDEO camera and will then buy whatever SLR does video best, however it will likely still not be a "full frame" SLR. For larger frame size the move from DX to FX is not enough to really matter much. I shot with a Mamiya RB67 for years and you DO notice the larger frame size once you get that large.

 

[Bear]

I have the same D200. As long is the final output medium is an electronic screen, I expect I will never run into any limitations. That said, Eventually I will want to upgrade my VIDEO camera and will then buy whatever SLR does video best
...

D200 is also fine for the sizes I print pictures at which is up to 13" x 19". And if I ever decide I want a video camera, I would just get a new D-SLR that does video.

 

[Policar]

1) The biggest question is how are you images displayed? Do you make large size prints (bigger than 8x10, maybe 24" wide or larger) or do you only look at them in an electronic screen? All screen have such poor resolution that yu don't see much if any improvement in quality, the screen itself is the bottleneck.

As long is the final output medium is an electronic screen, I expect I will never run into any limitations. That said, Eventually I will want to upgrade my VIDEO camera and will then buy whatever SLR does video best, however it will likely still not be a "full frame" SLR. For larger frame size the move from DX to FX is not enough to really matter much. I shot with a Mamiya RB67 for years and you DO notice the larger frame size once you get that large.

You're coming across as a bit of a luddite. I hate to say it (because I'm about to sell my 5D Mark III and go back to APS-C), but FF digital is much better than you're giving it credit for being; I'd put it on par with 6x7 film easily. Yes, there's less resolution, but it's so much cleaner that even at low ISOs you can print arguably larger with FF digital than with 6x7 film and there's more microcontrast than with 135 for sure.

Both FF digital (with the best lenses) and 6x7 film have a "punchiness" that lesser formats (135 film and APS-C digital) lack. Not so much for landscapes, which are approaching diffraction limited on most any system, and for which 4x5 is the superior format no question, but for portraiture you can use shallow focus lenses with good resolution and excellent microcontrast and the medium itself has enough acutance not to get fuzzy. The "awesome" look of f2.8 normals wide open shot with a Mamiya or Hasselblad is awfully easy to recreate with FF and a 50mm or 85mm f1.2 lens or even one of the cheap alternatives.

6x7 film has been totally supplanted by FF digital. I've shot both; I've seen prints of both... and neither is a landscape format, anyway.

As regards 4x5, you need a drum scan to really make the difference. And that's what? $100 per shot to scan. If you bracket, it's about $20 per shot to shoot. But I do think 4x5 is the best format for landscape, no comparison. It's also a little trickier to shoot for sure, at least for me... I find it quite slow by comparison.

So for fashion and product photography go 5D or 6D. For sports or nature go 1DX. For landscape I do agree 4x5 is awesome! But my Hasselblad love is purely nostalgic now.

 

[swordio777]

I am wondering:

1- Is there really a huge benefit for a beginner, in going FF? Will this open up a new world of possibilities for me?

Nope! FF is a luxury - definitely not a requirement. It will certainly not allow you to do anything that you can't already do on your crop camera with the correct lens & correct technique.

2- Is FF going to make things more complex for me? Is it a step in the right direction? Or not really? Is it more a case of "each frame size has its uses".

It honestly doesn't make photography any easier or any more difficult. Other aspects of some Pro-level FF cameras can make your life easier (such as greatly improved autofocus), however sensor size will not affect how "easy" the camera is to use, or how "easy" it is to create the shot you see in your head. Only practice will accomplish both.

3- What would I lose by going FF? What would I gain?

You'll lose money. Fast! Full frame body means full frame lenses and they are generally significantly more expensive than their crop counterparts. They're also generally quite a bit heavier, so you could potentially also lose your health if you're carrying it for long periods.
What you'll gain is a bit harder to pin down - My belief is that generally FF cameras have a slightly greater dynamic range, HOWEVER this gap is closing all the time.

Good comments/questions.
The appeal of FF, to me, seems to be motivated by:

1. A desire to "upgrade" (subjective, I know..When not backed up with a real need).
2. The idea that I can gain a "better image" (sharper, better DOF, etc.) and gain width of field on the shorter end (landscape, specifically).
Does that make sense?

FF sensors can APPEAR to give you a shallower depth of field because they allow you to get closer to your subject to frame the same shot. This is actually a negative if you're doing a lot of landscape work though where you'll want as much DOF as you can get. If you want shallow DOF for taking portraits then drop $100 on a 50mm f1.8 - it will get you 90% of the way to a 24-70 f2.8 on an FF body for a tiny fraction of the cost.

I really hope my answers don't sound facetious. Like you, I play guitar - and I know all too well what gear lust is like (both for camera and music equipment). But from what you've described in this thread I honestly think spending a large sum of money on a FF camera would be crazy at this point in your hobby.

The sage advice of people who have been playing / shooting for years is unfortunately true - the key to mastery is not new toys & gadgets, but practice, practice, practice. You already have a fantastic camera, so make the most of it & shoot as much as you can.

Hope that helps.

 

[Puckman]

You're coming across as a bit of a luddite. I hate to say it (because I'm about to sell my 5D Mark III and go back to APS-C), but FF digital is much better than you're giving it credit for being; I'd put it on par with 6x7 film easily. Yes, there's less resolution, but it's so much cleaner that even at low ISOs you can print arguably larger with FF digital than with 6x7 film and there's more microcontrast than with 135 for sure.

Both FF digital (with the best lenses) and 6x7 film have a "punchiness" that lesser formats (135 film and APS-C digital) lack. Not so much for landscapes, which are approaching diffraction limited on most any system, and for which 4x5 is the superior format no question, but for portraiture you can use shallow focus lenses with good resolution and excellent microcontrast and the medium itself has enough acutance not to get fuzzy. The "awesome" look of f2.8 normals wide open shot with a Mamiya or Hasselblad is awfully easy to recreate with FF and a 50mm or 85mm f1.2 lens or even one of the cheap alternatives.

6x7 film has been totally supplanted by FF digital. I've shot both; I've seen prints of both... and neither is a landscape format, anyway.

As regards 4x5, you need a drum scan to really make the difference. And that's what? $100 per shot to scan. If you bracket, it's about $20 per shot to shoot. But I do think 4x5 is the best format for landscape, no comparison. It's also a little trickier to shoot for sure, at least for me... I find it quite slow by comparison.

So for fashion and product photography go 5D or 6D. For sports or nature go 1DX. For landscape I do agree 4x5 is awesome! But my Hasselblad love is purely nostalgic now.

1) The biggest question is how are you images displayed? Do you make large size prints (bigger than 8x10, maybe 24" wide or larger) or do you only look at them in an electronic screen? All screen have such poor resolution that yu don't see much if any improvement in quality, the screen itself is the bottleneck.

2) Why go to "only" FF? If you'd like to change formats and you shoot landscapes why pick a 36mm x 24 mm frame size? Traditionally people used 36x24mm because that was all they could afford. But now 36x24mm has becaome one of the most expensive formats. Have you considered other sizes and do you have a good reason not to use them?

You caould buy an entire used Hasselblad system for the price of a Canon 6D body. And obviously the Hasselblad would just blow the 6D ouot of the water in terms of image quality

Why not shoot 4x5? Seriously. Don't say if costs to much not if you can afford a FF dSLR. 4x5 is cheaper Keep the Canon and buy a large format. That will make a HUGE difference in your work. But NO ONE BUT YOU will see any difference if you move to a FF Canon, the difference is to subtle to notice for most people. The 4x5 is way cheaper and will outperform even the Hasselblad.

I'd say keep the APS-C sized Canon for it's portability and if you want better quality images make the jump away fro small format altogether.

----------



I have the same D200. As long is the final output medium is an electronic screen, I expect I will never run into any limitations. That said, Eventually I will want to upgrade my VIDEO camera and will then buy whatever SLR does video best, however it will likely still not be a "full frame" SLR. For larger frame size the move from DX to FX is not enough to really matter much. I shot with a Mamiya RB67 for years and you DO notice the larger frame size once you get that large.

Both above comments were way above my level of knowledge and understanding, unfortunately. As I mentioned, I'm a newbie to photography. Print sizes, Hasselback systems, and all that is way beyond me.
I appreciate you both taking the time to offer your opinions though. I'll have to re-read this stuff when I know a bit more about what's being discussed.

----------

Nope! FF is a luxury - definitely not a requirement. It will certainly not allow you to do anything that you can't already do on your crop camera with the correct lens & correct technique.


It honestly doesn't make photography any easier or any more difficult. Other aspects of some Pro-level FF cameras can make your life easier (such as greatly improved autofocus), however sensor size will not affect how "easy" the camera is to use, or how "easy" it is to create the shot you see in your head. Only practice will accomplish both.


You'll lose money. Fast! Full frame body means full frame lenses and they are generally significantly more expensive than their crop counterparts. They're also generally quite a bit heavier, so you could potentially also lose your health if you're carrying it for long periods.
What you'll gain is a bit harder to pin down - My belief is that generally FF cameras have a slightly greater dynamic range, HOWEVER this gap is closing all the time.


FF sensors can APPEAR to give you a shallower depth of field because they allow you to get closer to your subject to frame the same shot. This is actually a negative if you're doing a lot of landscape work though where you'll want as much DOF as you can get. If you want shallow DOF for taking portraits then drop $100 on a 50mm f1.8 - it will get you 90% of the way to a 24-70 f2.8 on an FF body for a tiny fraction of the cost.

I really hope my answers don't sound facetious. Like you, I play guitar - and I know all too well what gear lust is like (both for camera and music equipment). But from what you've described in this thread I honestly think spending a large sum of money on a FF camera would be crazy at this point in your hobby.

The sage advice of people who have been playing / shooting for years is unfortunately true - the key to mastery is not new toys & gadgets, but practice, practice, practice. You already have a fantastic camera, so make the most of it & shoot as much as you can.

Hope that helps.

This makes a lot of sense, and I am starting to lean more and more towards this notion. I will hold off on upgrading my camera for the time being, and focus on practice and improving my photography itself, without worrying about equipment, until, at least, I start hitting any limitations imposed on me by said equipment (which will probably not happen anytime soon).

Thanks all for your input. That was very helpful.

And cheers to a fellow musician/guitar player. You totally got where i was coming from (the gear lust issue is probably even worse with guitars than it is with photography equipment).

 

[Razeus]

Nothing, if you can't take good photos and don't understand light and composition.

 

[OreoCookie]

FF sensors can APPEAR to give you a shallower depth of field because they allow you to get closer to your subject to frame the same shot. This is actually a negative if you're doing a lot of landscape work though where you'll want as much DOF as you can get. If you want shallow DOF for taking portraits then drop $100 on a 50mm f1.8 - it will get you 90% of the way to a 24-70 f2.8 on an FF body for a tiny fraction of the cost.

Larger sensor don't appear to give a shallower depth of field, they do give a shallower depth of field if you use equivalent focal lengths (so that the viewing angle stays the same).

 

[nburwell]

First and foremost, if your camera body isn't holding you back at all, then I would suggest you upgrade your lenses. A suggestion off the top of my head would be to sell both the Canon EF-S 18-55mm and the Sigma 18-200mm and buy the Canon EF-S 17-55mm f/2.8 and maybe even the Canon EF 70-200mm f/4.

If you have the disposable income available to you to upgrade your body, then by all means do it. However, don't be surprised if you don't see a drastic improvement in your photography because you went FF. Since you mentioned you're still a newbie, I would get a firm handle on knowing how to fully operate your T3i. What mode do you usually shoot in anyway?

Just a quick Flickr search of "Canon EOS T3i + landscapes" brought up the results below:
http://www.flickr.com/search/?q=canon+eos+t3i,+landscape&s=int

There are some really awesome photos taken by photographers who own the T3i. So definitely look at upgrading your lens lineup first.

With that said, the 6D is a awesome camera in and of itself. I wouldn't blame you if you ended up purchasing the 6D, but you will need to get a nice mid range lens since both your 18-55mm and 18-200mm will not work on a FF sensor camera. So basically, if you did upgrade to FF, your 50mm would work with the 6D, but you would have to get a standard lens (you could purchase the 6D + EF 24-105mm packaging).

Best of luck in whatever route you decide to go.

 

[swordio777]

@OreoCookie
Sensor size itself has absolutely no effect on depth of field. Only 3 things affect depth of field: focal length, subject distance, and aperture.

With all three of these factors being equal, both crop and FF sensors will have identical depth of field. However, the image produced from each sensor will differ because the CROP sensor is doing exactly what it's name suggests - cropping out the edges of the frame.

People often wrongly think of a crop sensor as having a 1.5x multiplier, however nothing is being multiplied and this description can often confuse new users. Crop sensors are not zooming in - they crop out the edge of the frame which means you have to get further away from your subject to fit it in.

You corrected your own error when you said:

they do give a shallower depth of field if you use equivalent focal lengths (so that the viewing angle stays the same).

but the thing that's altering the DOF is not the size of the sensor - it is the fact that you need to either use a different focal length, or be a different distance from the subject to frame a similar shot.

 

[OreoCookie]

@OreoCookie
Sensor size itself has absolutely no effect on depth of field. Only 3 things affect depth of field: focal length, subject distance, and aperture.

Your explanation is correct, but it does not contradict what I have written: I have always added the qualifier that you need to consider equivalent focal lengths (meaning the same viewing angle), I don't see where »I have corrected my mistake.« For instance, I wrote in my first post in this thread:

(4) Narrower depth of field on equivalent lenses

Photographers choose lenses based on the viewing angle, because they're determining the look of an image. And to get the same viewing angle, you have to use a shorter focal length on smaller sensors.