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Author Topic: Canon EF 50mm f1.4 USM on a 1.6 Crop Body?  (Read 16617 times)

timescapes

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Canon EF 50mm f1.4 USM on a 1.6 Crop Body?
« on: July 11, 2008, 03:20:57 pm »

I'm looking for a fast, cheap lens that I can put on a Canon XT or XSi body that will let me shoot in low light.  80mm focal length is fine.

When you put an EF lens on an EF-S body, isn't the camera essentially only using the center of the glass, where it is sharpest?

In other words, wide open, the EF 50mm f1.4 might have a lot of distortion at the edges of frame (when used on a FF body), but on a cropped-sensor body, I wouldn't even be seeing the extreme edges of the lens, would I?
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juicy

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Canon EF 50mm f1.4 USM on a 1.6 Crop Body?
« Reply #1 on: July 11, 2008, 03:36:56 pm »

Quote
I'm looking for a fast, cheap lens that I can put on a Canon XT or XSi body that will let me shoot in low light.  80mm focal length is fine.

When you put an EF lens on an EF-S body, isn't the camera essentially only using the center of the glass, where it is sharpest?

In other words, wide open, the EF 50mm f1.4 might have a lot of distortion at the edges of frame (when used on a FF body), but on a cropped-sensor body, I wouldn't even be seeing the extreme edges of the lens, would I?
[a href=\"index.php?act=findpost&pid=207376\"][{POST_SNAPBACK}][/a]

You are right, you won't see the edges. If you shoot buildings or similar subjects you may sometimes see a hint of barrel distortion even with a crop sensor with this lens. For people photography it's sharp from f2 in my experience and very sharp @ f4 - f8.

Cheers,
J
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timescapes

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Canon EF 50mm f1.4 USM on a 1.6 Crop Body?
« Reply #2 on: July 11, 2008, 03:43:23 pm »

Quote
You are right, you won't see the edges. If you shoot buildings or similar subjects you may sometimes see a hint of barrel distortion even with a crop sensor with this lens. For people photography it's sharp from f2 in my experience and very sharp @ f4 - f8.

Cheers,
J
[a href=\"index.php?act=findpost&pid=207380\"][{POST_SNAPBACK}][/a]

Will I still get the speed advantage of f/1.4 or f/2 on my cropped-sensor body?  Right now I shoot at f/3.5 on my EF-S 10-22, so any speed advantage over that would be very helpful for my night shots.

thanks
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juicy

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Canon EF 50mm f1.4 USM on a 1.6 Crop Body?
« Reply #3 on: July 11, 2008, 03:59:29 pm »

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Will I still get the speed advantage of f/1.4 or f/2 on my cropped-sensor body?  Right now I shoot at f/3.5 on my EF-S 10-22, so any speed advantage over that would be very helpful for my night shots.

thanks
[a href=\"index.php?act=findpost&pid=207383\"][{POST_SNAPBACK}][/a]

There's no difference in lens speed with different size sensors. It's 1.4. Anyway you will get many slightly missfocused images shooting wide open because the depth of field is really tiny. And some dreamy softness plus color aberration etc. But sometimes that kind of images are wonderfull and there's a huge difference between 1/13s @ f1.4 and half a second @ f3.5 when you are already at iso1600.

Cheers,
J
« Last Edit: July 11, 2008, 04:00:03 pm by juicy »
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timescapes

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Canon EF 50mm f1.4 USM on a 1.6 Crop Body?
« Reply #4 on: July 11, 2008, 04:09:35 pm »

Quote
There's no difference in lens speed with different size sensors. It's 1.4. Anyway you will get many slightly missfocused images shooting wide open because the depth of field is really tiny. And some dreamy softness plus color aberration etc. But sometimes that kind of images are wonderfull and there's a huge difference between 1/13s @ f1.4 and half a second @ f3.5 when you are already at iso1600.

Cheers,
J
[a href=\"index.php?act=findpost&pid=207389\"][{POST_SNAPBACK}][/a]

Will it be difficult for me to find infinity at night on the EF 50mm f1.4?

I think half the time the only reason I am able to keep my dark sky shots in focus is because the 10-22 has such massive DOF at 10mm.
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juicy

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Canon EF 50mm f1.4 USM on a 1.6 Crop Body?
« Reply #5 on: July 11, 2008, 04:16:17 pm »

Quote
Will it be difficult for me to find infinity at night on the EF 50mm f1.4?

I think half the time the only reason I am able to keep my dark sky shots in focus is because the 10-22 has such massive DOF at 10mm.
[a href=\"index.php?act=findpost&pid=207392\"][{POST_SNAPBACK}][/a]

Haven't tried.
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Bill Caulfeild-Browne

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Canon EF 50mm f1.4 USM on a 1.6 Crop Body?
« Reply #6 on: July 11, 2008, 04:47:55 pm »

Quote
Will it be difficult for me to find infinity at night on the EF 50mm f1.4?

I think half the time the only reason I am able to keep my dark sky shots in focus is because the 10-22 has such massive DOF at 10mm.
[a href=\"index.php?act=findpost&pid=207392\"][{POST_SNAPBACK}][/a]

I suggest you focus on a distant object in daylight, mark the position with a tiny piece of tape or something, and replicate that setting at night.
Bill
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stever

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Canon EF 50mm f1.4 USM on a 1.6 Crop Body?
« Reply #7 on: July 11, 2008, 06:32:09 pm »

am i missing something here?  infinity is with the ring turned to the left (looking at the top of the camera - you can feel extra resistance when you get to infinity

this lens works great on a crop frame camera and in some ways is more useful than on full frame - however it's better stopped down to f2 even on a crop-frame camera
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Panopeeper

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Canon EF 50mm f1.4 USM on a 1.6 Crop Body?
« Reply #8 on: July 11, 2008, 08:40:59 pm »

Quote
am i missing something here?  infinity is with the ring turned to the left (looking at the top of the camera - you can feel extra resistance when you get to infinity
Yes, you are, namely the user's guide of the lens, which says something like

the focusing ring can be turned past the infinity mark (the short leg of the L)
to compensate for shifting of the infinity focus point that results from changes in temperature

and

The infinity position at normal temperature is the point at which the vertical line of the L mark is aigned with the distance indicator

Now, you know why your manually focused images at infinity have always been out of focus :-)
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Gabor

Misirlou

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Canon EF 50mm f1.4 USM on a 1.6 Crop Body?
« Reply #9 on: July 11, 2008, 10:45:03 pm »

Quote
Will it be difficult for me to find infinity at night on the EF 50mm f1.4?

I think half the time the only reason I am able to keep my dark sky shots in focus is because the 10-22 has such massive DOF at 10mm.
[a href=\"index.php?act=findpost&pid=207392\"][{POST_SNAPBACK}][/a]

This is one of those situations where LiveView can be really helpful. If your camera dosen't have that, you might try a focus magnifier for night shots.

The zone of acceptable focus at f1.4 is incredibly narrow. Lots of people complain about the 50/1.4 being soft wide open, and I've often wondered if it's just too darn hard for a lot of them to focus. Or maybe they get the focus right but don't realize that just a little bit of movement between focussing and tripping the shutter might disturb the distance relationship, and thus the focal plane.

My old Olympus 50/1.4 had a very curved field at the film plane, at least wide open. The standard "focus then recompose" method was a disaster with that lens. I haven't noticed that with the Canon, but with autofocus cameras, I usually manually select which focus sensor to use anyway.

The 50/1.4 makes a really fun portrait lens on a crop body camera. Great for street shots at night as well, providing you master the focus.
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JohnIgel

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Canon EF 50mm f1.4 USM on a 1.6 Crop Body?
« Reply #10 on: July 11, 2008, 11:36:00 pm »

Quote
When you put an EF lens on an EF-S body, isn't the camera essentially only using the center of the glass, where it is sharpest?

In other words, wide open, the EF 50mm f1.4 might have a lot of distortion at the edges of frame (when used on a FF body), but on a cropped-sensor body, I wouldn't even be seeing the extreme edges of the lens, would I?
[{POST_SNAPBACK}][/a]
Take a look at this it might help you perceive the difference between full frame and APS-C sensors using this lens:

[a href=\"http://www.slrgear.com/reviews/showproduct.php/product/140/cat/10]http://www.slrgear.com/reviews/showproduct...duct/140/cat/10[/url]
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timescapes

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Canon EF 50mm f1.4 USM on a 1.6 Crop Body?
« Reply #11 on: July 11, 2008, 11:56:47 pm »

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This is one of those situations where LiveView can be really helpful. If your camera dosen't have that, you might try a focus magnifier for night shots.

The zone of acceptable focus at f1.4 is incredibly narrow. Lots of people complain about the 50/1.4 being soft wide open, and I've often wondered if it's just too darn hard for a lot of them to focus. Or maybe they get the focus right but don't realize that just a little bit of movement between focussing and tripping the shutter might disturb the distance relationship, and thus the focal plane.

I shoot long-exposure night astro landscapes, so I don't think live view can help me.  

I was at Samy's today looking at the EF 28mm f1.8, which might be a better lens for me, now that I think about it.  Probably a lot easier to find infinity at night (with cold temperatures) than on the 50mm.  Plus the FOV is better suited to landscape work.

Do you guys think I could shoot wide open on the 28mm f1.8 with a cropped-sensor 350D?  I imagine that the crop factor would spare me some distortion at the edges?

Also, if I upgrade to the new 5D or a 1Ds, will the 28mm f1.8 still be of any value to me on a camera with that much resolution?  I'm trying to spend money on lenses with an eye toward upgrading my whole kit to full frame at some point.

Of course another option would be the 24mm 1.4 L.  But I would feel kind of crazy putting a $1,200 lens on a $400 camera.
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Misirlou

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Canon EF 50mm f1.4 USM on a 1.6 Crop Body?
« Reply #12 on: July 12, 2008, 12:44:31 am »

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I shoot long-exposure night astro landscapes, so I don't think live view can help me.  [a href=\"index.php?act=findpost&pid=207500\"][{POST_SNAPBACK}][/a]

You would just use LiveView to focus, then shut it off. On something like a 40D, you hit the set button, which engages LiveView, then you use the + button to magnify the central area of the sensor. So you're seeing a much larger view of the object you're trying to focus. Focus manually, then hit the set button to turn off LiveView. Takes about 2 seconds. Effectively, it's just allowing you to use the LCD screan as a focus magnifier.

Several astro imagers I know use LiveView for focussing. I don't, because I have several friends who are astro imagers, and I just let them do the imaging for me.
« Last Edit: July 12, 2008, 12:51:02 am by Misirlou »
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sojournerphoto

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Canon EF 50mm f1.4 USM on a 1.6 Crop Body?
« Reply #13 on: July 12, 2008, 05:19:18 am »

Just to back up the earlier comments, the 50 1.4 is a lovely lens. Not the most perfect lens in terms of distortion etc, but it sits on my full frame cameras and gets more use than anything else. Liveview for focusing is excellent.

Mike
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ryepixels

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Canon EF 50mm f1.4 USM on a 1.6 Crop Body?
« Reply #14 on: July 12, 2008, 10:03:53 am »

I have 50mm 1.4 on my 40D. It's OK for inside (poor light) shots at ISO200-400 but hand held with moving children and very shallow DoF you will still get "misses". But with fast fps on 40D I typically take bursts of 3-4 shots and will typically get 1-2 focussed. This is where digital really comes to fore over film, hey!

AF is not as fast on this lens as my L lenses, and it does hunt in lower light situations - for dark sky I'd imagine you'd want to turn AF off anyway.

For posed portraits with better light (near window, reflector or off camera lights) and camera on a tripod, this lens produces great portraits.

BTW I use the 10-22 for landscapes and wouldn't consider using the 50mm - just not wide enough - and most of the time I'm shooting f11 or above ...
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timescapes

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Canon EF 50mm f1.4 USM on a 1.6 Crop Body?
« Reply #15 on: July 12, 2008, 11:10:09 am »

Quote
You would just use LiveView to focus, then shut it off. On something like a 40D, you hit the set button, which engages LiveView, then you use the + button to magnify the central area of the sensor. So you're seeing a much larger view of the object you're trying to focus. Focus manually, then hit the set button to turn off LiveView. Takes about 2 seconds. Effectively, it's just allowing you to use the LCD screan as a focus magnifier.

Several astro imagers I know use LiveView for focussing. I don't, because I have several friends who are astro imagers, and I just let them do the imaging for me.
[a href=\"index.php?act=findpost&pid=207504\"][{POST_SNAPBACK}][/a]

A lot of my dark sky shots might be 20 or 30 second exposures.  How does Live View work in that case?  Couldn't I just as easily take sample shots?  I don't have any experience trying to focus from an LCD.  Maybe with the new 3" LCDs it will be easier.
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Misirlou

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Canon EF 50mm f1.4 USM on a 1.6 Crop Body?
« Reply #16 on: July 12, 2008, 10:04:12 pm »

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A lot of my dark sky shots might be 20 or 30 second exposures.  How does Live View work in that case?  Couldn't I just as easily take sample shots?  I don't have any experience trying to focus from an LCD.  Maybe with the new 3" LCDs it will be easier.
[a href=\"index.php?act=findpost&pid=207618\"][{POST_SNAPBACK}][/a]

It wouldn't make any difference at all. You'd just be turning on LiveView to focus, then turning it off before you shoot. When you go to shoot, the camera is back to the way it was. Again, you could activate LiveView, focus manually (using an enlarged view), then deactivate it in the space of two seconds.

I suppose you could use it to frame as well, but you only activate it when you need it any case. If it's turned off, it doesn't do anything to exposures.

Sample shots would only tell you if your focus was off. They would not help you focus correctly in the first place.

Really, LiveView is no big deal. At first, a lot of experienced shooters complained that adding it to DSLRs was "dumbing them down" or something, as if they expected to find people holding DSLRs at arm's length with the screen on, just as they do with point and shoots. As it turns out, a lot of serious shooters find it useful as an electronic focus magnifier. Just the thing for macro, or any situation where focus might be difficult.

And there's no shame in admitting difficulty manually focussing a DSLR. In the manual focus film days, we often had split prisms and other focusing aids to help. As autofocus and digital came along, the focus screens in SLRs were altered to fit the new technology. For example, slow zooms turned split prisms dark. Since so many consumers were buying slow zooms for their autofocus cameras, the manufacturers just got rid of split prisms. Great for autofocus, not so great for manual focus. Recognizing this, newer DSLRs with interchangeable focus screens usually have one optionally available that has been specifically designed to make manual focus easier.
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timescapes

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Canon EF 50mm f1.4 USM on a 1.6 Crop Body?
« Reply #17 on: July 12, 2008, 11:01:31 pm »

How does Live View accumulate enough light to show me what a 30-second shot is going to look like?
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Misirlou

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Canon EF 50mm f1.4 USM on a 1.6 Crop Body?
« Reply #18 on: July 12, 2008, 11:35:07 pm »

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How does Live View accumulate enough light to show me what a 30-second shot is going to look like?
[a href=\"index.php?act=findpost&pid=207743\"][{POST_SNAPBACK}][/a]

Depending on the model of camera, and your settings, they can simulate the exposure to some extent. The camera's processor just amplifies the heck out of whatever it is that the sensor is reading, and displays that amplified image on the LCD. For example, a 40D alllows you to turn exposure simulation on or off easily with one of the custom functions. I've read that there are other cameras that have more sophisticated LiveView capabilties, but you wouldn't need much just to focus.

I wouldn't recommend leaving LiveView on for very long though, because the sensor will be in constant read mode while it's activated. That will build up heat in the sensor, which will increase noise. But I thought we were only discussing LiveView as a way to focus anyway, not to completely simulate your final shot. You don't need to see that resulting image to focus. You just need something (anything) that will help you manually focus very accurately, before you press the shutter.
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