Crop 50mm equivilent EF-S lens?

Myboostedgst wrote in post #18140450
Go back through and read your own posts. After your first post, every single post on page 1 (minus one post) contains something along the lines of "If they just built it I am sure they would sell a ton".

Do I have stock in Canon? Come on, are you serious? Yes, my whole retirement plan is to try and convince others on an internet forum to buy Canon products instead of third party options. I have made my point here, you are as concered with complaining about Canon's lack of a 30mm as you are with finding a valid choice. All of the options have been presented, and the only one that fits into your stipulations is the older non art Sigma 30mm 1.4. Good luck on your choice, maybe relaxing a bit will help you make a decision. I'll leave you be now before I get super upset and go on some sort of rampage or something.

Have you got nothing better to do?

CheshireCat wrote in post #18140557
SkipD, I must say your dogmatic posts are misleading.

The FL choice does indeed have a big effect on perspective, if the photographer's purpose is a particular subject framing (as it usually is).
For example, if I want a full-body portrait framing, I will need to stay closer to the subject with a 35mm lens than with a 85mm lens, therefore the FL choice will definitely affect perspective.

In other words, good photographers select the FL because they want a certain perspective based on the desired subject framing, therefore the FL does affect the perspective.

Focal length, IN ITSELF, has nothing to do with the perspective in an image made with the lens. We've proven that.

You don't need a lens on a camera to see changes in perspective (the relative sizes of elements of a scene at different distances from the camera or viewer). When I'm analyzing a scene to figure out where to put the camera, I'm simply using my eyes as I move around. As I change the distance between my head and the scene, I can see the changes in perspective. The focal length of my eyes is not changing while doing this. When I've found the position where the perspective is what I want, THEN I choose a focal length for my camera to frame the image the way I want it.

Changing the focal length with the camera at a fixed position only changes the framing of the image and does not affect perspective one bit.

I will agree that many experienced photographers choose a lens' focal length based on their intended use such as for a head-n-shoulders portrait. They have done the same type of shot over and over and know that the focal length works. This sort of thing does not change the basic fact that the focal length chosen does not affect the perspective in an image. It's where the camera is placed that makes that difference.

SkipD wrote in post #18140638
Focal length, IN ITSELF, has nothing to do with the perspective in an image made with the lens. We've proven that.

You don't need a lens on a camera to see changes in perspective (the relative sizes of elements of a scene at different distances from the camera or viewer). When I'm analyzing a scene to figure out where to put the camera, I'm simply using my eyes as I move around. As I change the distance between my head and the scene, I can see the changes in perspective. The focal length of my eyes is not changing while doing this. When I've found the position where the perspective is what I want, THEN I choose a focal length for my camera to frame the image the way I want it.

Changing the focal length with the camera at a fixed position only changes the framing of the image and does not affect perspective one bit.

I will agree that many experienced photographers choose a lens' focal length based on their intended use such as for a head-n-shoulders portrait. They have done the same type of shot over and over and know that the focal length works. This sort of thing does not change the basic fact that the focal length chosen does not affect the perspective in an image. It's where the camera is placed that makes that difference.

You are being at best pedantic. He already stated the subjects framing was fixed. By definition that means he must change camera positions with fl changes to keep the subject framing fixed. Just because you are incapable of doing this other than moving your feet first rather than changing focal lengths first is inconsequential.

vengence wrote in post #18140796
You are being at best pedantic. He already stated the subjects framing was fixed. By definition that means he must change camera positions with fl changes to keep the subject framing fixed. Just because you are incapable of doing this other than moving your feet first rather than changing focal lengths first is inconsequential.

I'm sorry but it appears that you don't understand the nature of this conversation.

Just because you have restricted your needs/desires to a certain framing, and only have a small set of focal length lenses available to you to shoot that subject, and/or location changes to make that framing happen, doesn't mean focal length dictated your perspective. You end up choosing your distance/position relative to the subject given your various inputs and your own requirements, and that final positional decision dictates perspective.

SkipD wrote in post #18140824
I'm sorry but it appears that you don't understand the nature of this conversation.

You are correct, I was incorrect in assuming you might only be being pedantic. Have a nice day.

I agree with the ChestireCat's assessment, the focal length doesnt change perspective argument is somewhat misleading. On a technicality matter, sure, it's true, but it would leave an uneducated student to believe that focal length doesnt matter, it does matter.

if I told someone best to take half body portraits with a 135mm rather than 35mm, I cant really then say that all that matters is distance, not focal length.... that's somewhat confusing and can be misleading.

it's kind of like thinking backwards.

for instance, the requirement is to do a headshot, you immediately grab a 135mm or longer lens because that focal length works well for those situations, rather than find your distance, then get the right focal length. On a practical matter, I think the flow doesnt work that way. By default, you have to move based on focal length and framing.

If I told a noobie use 200mm for the headshot and he owns a 28-300, then he can figure it out, much easier than telling him some arbitrary distance, which he/she may not be able to figure out, not like we carry yardsticks everywhere.

Charlie wrote in post #18141090
I agree with the ChestireCat's assessment, the focal length doesnt change perspective argument is somewhat misleading. On a technicality matter, sure, it's true, but it would leave an uneducated student to believe that focal length doesnt matter, it does matter.

if I told someone best to take half body portraits with a 135mm rather than 35mm, I cant really then say that all that matters is distance, not focal length.... that's somewhat confusing and can be misleading.

it's kind of like thinking backwards.

for instance, the requirement is to do a headshot, you immediately grab a 135mm or longer lens because that focal length works well for those situations, rather than find your distance, then get the right focal length. On a practical matter, I think the flow doesnt work that way. By default, you have to move based on focal length and framing.

If I told a noobie use 200mm for the headshot and he owns a 28-300, then he can figure it out, much easier than telling him some arbitrary distance, which he/she may not be able to figure out, not like we carry yardsticks everywhere.

There are many reasons why I (and many others) feel that teaching the truth about perspective control is so that creative photographers can think their way through problem solving.

One typical perspective control issue that I use as an example is doing a family snapshot with scenic mountains in the background. By crawling up on the family with a camera using a short focal length, the mountains often become far less than majestic-looking. However, backing up to twice the distance from the family and then choosing a different focal length (twice the original) to frame the family will provide mountains that are twice the size in the background.

SkipD wrote in post #18139381
Secondly, as I mentioned above, focal length, by itself, isn't what affects perspective in our images. The distance(s) from the camera to the various elements of the scene in front of the camera are what affect perspective. Please read our "sticky" (found in the General Photography Talk forum) tutorial titled Perspective Control in Images - Focal Length or Distance?.

It is actually the angular size of the subject, not distance etc., which is the only primary factor defining the perspective effects. A toy house 10cm high located 10cm away from your camera will have the same perspective distortion as a 10m high house located 10m away. Perspective distortion is an effect occurring when trying to project the spherical world onto a flat sensor, and the larger the angular size of the subject the stronger the effect is. (For the same reason, the larger the country/continent is, the more distorted its map is.) If we use spherical sensors, and project the resulting image on a spherical dome (think planetariums), there will be no perspective distortion.

pulsar123 wrote in post #18141855
If we use spherical sensors, and project the resulting image on a spherical dome (think planetariums), there will be no perspective distortion.

This will probably solve a host of other lens aberrations (maybe all?). And lenses won't need to be rectilinear so they'd probably be cheaper and lighter.

Doing the spherical sensor/projection thing would be great, but then you would really have to view the resulting image from the loci of the radius to see the correct effect without creating some distortion in the apparent relationship between objects in the scene. Still I guess the distortion is likely to be less than for attempting to project onto a plane, unless you get significantly far away from the loci.

Alan

STIC wrote in post #18139159
With the prevalence (and the improving quality) of crop bodies, how come canon haven't released an EF-S 31mm f1.8 (or even better f1.4) for use on crops as a 50mm?

I got the EF-S 15-85 bundled with the 7DII and it's a really nice lens, but I'd love a 50mm equivalent EF-S...

My Canon 35mm f/2 IS USM has a 35mm equivalent angle of view similar to 56mm. Isn't that close enough? Even a 30mm crop lens would be off with a 35mm equivalent of 48mm. Does a few mm more of less really make that much of a difference to you? For close in subjects it a question of taking a half step forward or backward to get the same framing. I have the original Sigma 30mm f/1.4 lens and I like it a lot, but much prefer the Canon 35mm f/2 IS for image quality

STIC wrote in post #18139211
No, it's about getting the 'human eye equivalent' perspective (so, shooting exactly what you are seeing) and, just as important, a nice wide aperture.

If I did have a FF, then my 50 f1.8 would give me this, but I have a 7DII so i'd like an EF-S lens that gives me this...

I still maintain that, if canon build it. it will sell...

If you want to look at a subject through the viewfinder and then look at the same subject with the naked eye and expect them to be identically sized that's not going to happen with a 50mm equivalent on a crop camera. With a 35mm lens on my 7D II or 60D the images through the viewfinder are much smaller. Perhaps when viewing at infinity they are closer in size. On my 7D II I would need to use a 50mm lens with an 80mm equiv. angle of view for the viewfinder view to be similar sized to the naked eye

STIC wrote in post #18139577
The wife will NOT sign off on a $1500 35L...

I'd be happy with an EF-S 30mm f1.4 (at a reasonable price), and i'm sure many thousands of other canon crop owners would be too...COME ON Canon...

yeah, but at f3.5 or 4...

Disagree. I think with all the excellent 35mm lenses out there the market for 30mm crop lenses is very limited. I no longer regularly even use mine.

Gungnir wrote in post #18140177
I have the 30mm you're considering. One of two ef-s lenses kept after full frame became primary body.

It's brilliant. I love it.

You'll read lots about focus issues blah blah blah but most of that comes from those unwilling to learn the specific characteristics of a lens. Instant gratification or whinge online...

Contrast isn't up there with the Art version but it does give lovely warm tones.

I've had that same Sigma lens for years and have really enjoyed it, but the design does have some focus issues and it vignettes significantly at f/1.4 and its soft at the edges. The build quality is excellent though. I much prefer my Canon 35mm f/2 IS. The Tstop light transmission of the Sigma is 1.8 to 1.9 depending on the body its mounted on. The Tstop of the Canon is 2.0. So even though the Sigma is technically a whole stop wider than the Canon, the amount of additional light it lets through is almost negligible. The Canon is also much sharper in the center and especially from edge to edge and is a much better lens over all. The Sigma at f/1.4 will provide a shallower DoF even if it doesn't take in any more light than the Canon. I'm not knocking the older Sigma really, but it is easily bested by more current offerings.