Canon 5mm f/1.4

Hello,,

I just purchased the Canon 50mm f/1.4 for my rebel xt camera. I have taken

several shots and it seems like it loses focus not far from the center of the

subject,(maybe it's me)is this normal and could it be because my camera is not

full frame?

Thank You,

Keith

Are you shooting at f1.4 and putting the main subject in the center? If so, try stopping down, you'll be amazed at what "depth of field" is all about.

noo.. its sn f1.4 almost no depth of field..its a very good lens but very tricky to use... wheni use it to do portraits, the nose will be pin sharp but the eyes will be soft.. thats the nature of the F1.4 beast.. try it at f8 or f11 !

 

Dont think its you ro your camera... actually, try it with your camera in full auto mode and youll see what the camera sets it to!

good luck.

-zacker-

When shooting that lens wide open you should use manual focus. Nose in focus eyes out of focus is typical for an autofocus camera.

 

I used one for several years on an EOS 10s. This lens is razor sharp when used properly.

<i>Nose in focus eyes out of focus is typical for an autofocus camera.</i><p>

 

Depends on whether you know how to use autofocus or not.

In general, lenses are optically best at around the middle of their aperture range. It is here that aberrations are usually least apparent. 1.4's are very nice to have, but not just because of the increased exposure options. What they do is make the other lower apertures suffer less from lens aberrations by moving them closer to the center of the range. They also make the viewfinder nice and bright and make manual focusing easier by reducing D of F in the viewfinder, which makes it easier to see exactly where the plane of critical focus lies. You can use 1.4 if necessary for exposure or if desired for D of F effect, but understand that it won't be a totally sharp shot if you are near the subject. If you back away from the subject a bit, your D of F when focused on the same subject will increase. Your camera has a large enough sensor to get away with this and still get a decent sized image once cropped, although it does stink having to compose your image differently than you'd like due to equipment limitations. I would only use autofocus if it is too dark to focus manually or if you are shooting things in action. No computer will ever be able to know where you want to put your subject within the field of acceptably sharp focus.

 

Keith L.

I have the 50mm f1,4, and yesterday I had the 350D. But I was so fed up with the inconsistent AF-performance by the 350D, that I sold it and bought the 30D instead.

 

As already said f1,4 will give you very shallow DOF @ f1,4. And when you combine this with the not very precise AF on the 350D you're in for a hit and miss experience.

You need to put the appropriate focus point on the eyes. Don't lock-focus-recompose...with a lens wide open doing so is asking for out of focus images. I have that lens and it works fine....more often then not, it is user error...funny how the lens gets blame. ;-)

I have been testing the 50mm f1,4 and 350D against a flat brickwall with the center focuspoint activated, no recomposing, and it was still hit and miss. Please tell me about the user error, I have commited?

I have a 20d and a XT on long term loan. I did a AF test using a 50/1.4 anlong with 24-70L and 16-35L. The XT AF is inconsistant, the 20D always locks dead on. The 20D appently has a percision AF Center point to take advantage of f/2.8 and wider lenses, whereas the XT does not.

 

My 50/1.8 is the sharpet lens I own (16-35/2.8L, 24-70/2.8L, 70-200/2.8L is, 100-400L is, 10-22EFs, and tied with 100mm/2.8Macro. Its AF is dead on and works fine wide open (Choose center point, AF on eyes and recompse).

 

Mark

Why do you people tell him to use it at F8 or F11? Why not tell him to sell it and get a 50/8 or 50/11 right from the start?

 

Kinda pointless having 1.4 if you're not allowed to use it...

See my post above for exactly why I think it's not pointless.

 

Do cars ever REALLY need to go any faster than 70 mph? Just because they can go well over 100 doeesn't mean that's where they should always be used, or where they are performing at their best and most efficient. But they can go that fast, because it makes opertion at the most common speeds more efficient.

 

Keith

Ed H asked

 

"Why do you people tell him to use it at F8 or F11? Why not tell him to sell it and get a 50/8 or 50/11 right from the start?

Kinda pointless having 1.4 if you're not allowed to use it..."

 

One reason to have a very fast lens is in focusing and being able to see the subject. The lens allows one to compose wide open in low light but stops down automatically at the set f stop.

 

It is really difficult to just focus with an f/11 lens. Also when you need a lens that opens to 1.4 or 1.8 (stopping action in low light) it is really nice.

 

Using a lens at f/11 for a portrait just gives insurance that the subject's entire head is in focus.

 

If one likes the very selective focus look (eyes in focus, the rest of the head out) check out those lens babies at about $100. They are much cheaper than a 50 f/1.4