cropped sensor on a canon 7d?

[m.lomibao]

i just purchased a canon 7d last saturday, can anybody explain me the cons n pros of the cropped sensor? i was gonna get the 5d mk2 but it was out of my budget for now...

thanks..

[koolpenguin89]

Here you can see the difference in sensor size:
300px-Sensor_sizes_overlaid_inside.svg.png
The main visual differences you will notice (or not) will be that it is worse in low light (though still very good in low light) and the DOF won't get as shallow. Other than that, you just have to deal with your lenses being more cropped (1.6*) in than they would be on full frame, so your 28mm becomes a 45mm, your 50mm becomes an 80mm, etc, but they keep their native FOV's.

Hope this helps. Day to day, unless your used to using FF, the crop factor shouldn't bother you. DSLRs have incredible DOF and low light to begin with, and after a while you learn to compensate for the crop factor.

Dylan

[m.lomibao]

Oh man, I should have save more money for a canon 5d mk2 instead.... Thanks for the clarification though

[m.lomibao]

By the way .. Is there any lense to make it look Full sensor ?

[cgbier]

The 7d has a full sensor. Canon would be stupid to build sensors cut in half in any camera (joking here). There is no distinctive 35mm look, besides a somewhat shallower depth of field at the same focal length, aperture and camera-victim distance.

What you are mixing up is the - what I see as - 35mm hype. 35mm film in photography was born out of a compromise, just like 24p in movies. Leica just built a camera that could use readily available movie film to take pictures. That simply grew into a standard. If you talk about full frame, why not talking about 6x6, 6x7, 4x5, 5x7, 8x10 frames?

[Erik Bien]

As cg hints, talking about "full frame" or "crop factors" is a sure-fire way to confuse everybody, not least yourself.

In the context of motion pictures, 35mm film rolls through the camera vertically, with the sprocket holes on the left and right. A single frame may span two sprocket holes (Techniscope), three sprocket holes (MaxiVision), or four sprocket holes (Academy/Super35/anamorphic widescreen). It's only the width you can't change and, width-wise, APS-C size sensors are all pretty much within spitting distance of these "vertical" formats. 35mm cinema lenses are designed to cover (that is, project a large enough image circle to fully illuminate) frames of this general size.

However for still pictures, 35mm film usually travels through the camera horizontally, with the sprocket holes on the top and bottom. A single frame is much larger, spanning eight sprocket holes. Lenses need a correspondingly larger image circle in order to cover. VistaVision (aka "Lazy Eight") is a "horizontal" motion picture film format which uses lenses originally designed for still photography.

A larger format simply takes a bigger chunk of the image circle, yielding a wider field of view (where the scene is cut off by the frame edges). To achieve the same field of view on a smaller-format camera, switch to a wider lens. Longer lenses have shallower depth of field, therefore smaller-format cameras have deeper depth of field, when you change focal length for the same field of view. The depth of field characteristics of an APS-C sized sensor will thus be similar to most 35mm motion picture film formats, while a "full frame" DSLR performs more like a 35mm stills camera in terms of DoF.

[drapeama]

I never tried a full-frame sensor, but so far, with the lenses I have to play with, I find the T2i/550D to be satisfying enough.
I mean, I have a Nikon 50mm lens, which gives enough depth (which is usually what's most users are after) and I also have an Hoya 28mm that is wider, but with which I can achieve a similar depth...so.
All in all, I think you can achieve pretty much the same with both (cropped vs full-frame) it's only that you have to calculate the field of view with that 1.6x factor as Dylan explained.
The worst thing to deal with is the aliasing, but being cropped or full-frame, you'd have to deal with it anyway...

[Janke]

Oh man, I should have save more money for a canon 5d mk2 instead....

Why? You can do everything with the 7D as you can with the 5D, and you got lot of money left over for lenses etc.

I'm even very happy with my T2i/550D, costing just one third of the 5D...

By the way .. Is there any lense to make it look Full sensor ?

Yes. All lenses will. They will just be 1.6 x "longer" on the 7D than on a full-frame DSLR.

If you want to calculate the equivalent lens you need to use, divide by 1.6.

So, instead of a 50mm on a full-frame, use a 30mm, instead of a 28mm, use a 18mm, instead of a 135mm, use a 85mm - and so on.

Just consider the 1.6 crop factor, and you're all set!

[m.lomibao]

thanks guys...now that i understand all this cropped and full sensor business , i feel that i can start appreciating the 7d...

[cgbier]

I only had a 7D in my hand once (and never been a fan of Canon still cams), but you'll have a lot of fun with it! I double dare you!

[blondandfun]

When you say "you can do everything" that is misleading. You might have to spend more money on lenses with cropped sensor to get the lowlight capabilities that equal the 5d, wouldnt you?

My event this weekend i shoot with t3i im hiring shooter with 5d and a cheap zoom lens, so ill get the answer on my own.

[Janke]

You might have to spend more money on lenses with cropped sensor to get the lowlight capabilities that equal the 5d, wouldnt you?

The very same lenses work on Canon's cropped sensor DSLRs.

You do have to move a few feet back if you're using a 50mm/1.4 instead of a 30mm/1.4...

[m.lomibao]

The very same lenses work on Canon's cropped sensor DSLRs.

You do have to move a few feet back if you're using a 50mm/1.4 instead of a 30mm/1.4...

yeah thats what ive noticed yesterday when i tried my 50mm 1.4 on my 7d.... so basically its alll about moving back if i dont wanna buy a 30mm 1.4 and will still achieve the same looks right?

[Janke]

Exactically !

(There may be a very slight difference in DOF, but if you don't know it, you won't see it...)

[drapeama]

(There may be a very slight difference in DOF, but if you don't know it, you won't see it...)

Looks like what's my cat thinks: If I don't see you, you don't see me so I'm invisible!

[blondandfun]

The very same lenses work on Canon's cropped sensor DSLRs.

You do have to move a few feet back if you're using a 50mm/1.4 instead of a 30mm/1.4...

I was referring to low light, not that.

Wouldnt a cheap f3.5 kit lens get better low light on the 5d than t3i? If yes, then you have to spend more money on t3i lenses to get as good results....??????????

[Janke]

Why put a cheap f3.5 lens on an expensive 5D?

Seriously, the difference would be minute, basically only how much less noise there is in the larger sensor.

[cgbier]

If you are after the same DOF, you loose about 1/3 of a stop.... basically nothing.

[Bif]

I was referring to low light, not that.

Wouldnt a cheap f3.5 kit lens get better low light on the 5d than t3i? If yes, then you have to spend more money on t3i lenses to get as good results....??????????

It may fit on the mount but the coverage is not enough to work properly on the full frame sensor. True of all EF-S lenses.

Why put a cheap f3.5 lens on an expensive 5D?

Seriously, the difference would be minute, basically only how much less noise there is in the larger sensor.

For one thing it's image won't cover the larger sensor properly, and for those who've compared noise and low light coverage on the two sensors with similar lenses most did report a slight but not really noticeable difference.

yeah thats what ive noticed yesterday when i tried my 50mm 1.4 on my 7d.... so basically its alll about moving back if i dont wanna buy a 30mm 1.4 and will still achieve the same looks right?

Basically it's about understanding that 50mm on the 7D, T2i, T3i, and 60D gives a "portrait" telephoto perspective like just short of the 55mm end of the 18-55mm "kit" lens.

If you want a good low light "normal" lens to use on the 7D (and T3i) I suggest either the EF 28mm f1.8 or the Sigma 30mm f1.4 (my choice was the EF 28mm). That and the 50mm f1.4 you already have give you two choices of perspective AND low light performance.

But USE that 7D. It's built for it! Just get the lenses that do what you need and don't worry about "I shoulda got the 5DMkII". The 7D is later technology and the only real thing you miss out on is real ultra wide perspective if you get something like the 17-40mm "L" lens.

I also suggest if you can afford it, get the 17-40mm f4L (lighter to carry than the f2.8l). That lens with a UV filter on the front completes weather sealing on the 7D. I had my 7D with that lens out in moderate rain a few times without worrying about it getting wet. I just had a towel in the truck to wipe it down after each stop.

The 7D was my choice over the 5D MkII. Enjoy it.

Bruce Foreman

[m.lomibao]

It may fit on the mount but the coverage is not enough to work properly on the full frame sensor. True of all EF-S lenses.







For one thing it's image won't cover the larger sensor properly, and for those who've compared noise and low light coverage on the two sensors with similar lenses most did report a slight but not really noticeable difference.




Basically it's about understanding that 50mm on the 7D, T2i, T3i, and 60D gives a "portrait" telephoto perspective like just short of the 55mm end of the 18-55mm "kit" lens.

If you want a good low light "normal" lens to use on the 7D (and T3i) I suggest either the EF 28mm f1.8 or the Sigma 30mm f1.4 (my choice was the EF 28mm). That and the 50mm f1.4 you already have give you two choices of perspective AND low light performance.

But USE that 7D. It's built for it! Just get the lenses that do what you need and don't worry about "I shoulda got the 5DMkII". The 7D is later technology and the only real thing you miss out on is real ultra wide perspective if you get something like the 17-40mm "L" lens.

I also suggest if you can afford it, get the 17-40mm f4L (lighter to carry than the f2.8l). That lens with a UV filter on the front completes weather sealing on the 7D. I had my 7D with that lens out in moderate rain a few times without worrying about it getting wet. I just had a towel in the truck to wipe it down after each stop.

The 7D was my choice over the 5D MkII. Enjoy it.

Bruce Foreman

thanks bruce foreman....it all make sense now