my first DSLR a T7 - ok to use a USM with bad focus motor?

[ROMzombi]

I'm coming off S95 (lens error) S100 (lens error) S110 and an SX620hs. This is my first DSLR. I went to a camera shop today that is going out of business and found a 50mm 1.4 USM for free. I took some pictures with it using manual focus and it seems to be ok other than no autofocus. It it ok to use with a broken focus motor? I don't like the kit lens it came with as the focus is so slow going in and out before it settles on focus in a semi dark room. Sometimes it won't even let me take a picture. The powershot cameras didn't care, they would take a picture no matter what. I'm very new with DSLR so maybe I'm not doing something right or some setting is off.

[deebatman316]

This was in reference to the kit lens. Also the camera not locking focus in low light and not taking a picture.

[Anonymous]

The second part of his question asked why he is having trouble with his kit lens having slow or no focus in dark conditions, hence my comment. 

Here is his quote:

I don't like the kit lens it came with as the focus is so slow going in and out before it settles on focus in a semi dark room. I'm very new with DSLR so maybe I'm not doing something right or some setting is off.

[jrhoffman75]

Got it. Understood.

[shadowsports]

Greetings,

Free is great.  My advice.

Using something broken with something that's working is not a recipe for success.  Will it work, yes.  How long and how well is anyone's guess.  If you are stuck between a rock and hard place, sure.  

The cost to repair the lens would practically exceed the cost to replace.

EF 50mm f1.4 USM new $399, Used Like new $240

EF 50mm f1.8 STM new $125, Used  Excellent $78

Side by side there is no appreciable different in IQ or bokeh between the f1.4 or f1.8. 

You are not going to notice any speed difference in AF (USM vs STM) in this case.    

Me, I'd replace it.  Decide using the information provided above and use it in MF focus until a working replacement can be acquired.  Photography should be about enjoying your camera and getting the most from your gear.   

[ROMzombi]

* edit - I should as if I need to turn off autofocus in the camera software when using manual focus?

The kit lens i'm not really impressed with. It seems like I can focus faster or at a similar speed, manually.

I do like the F1.4 as opposed to F3.5 because of the bokeh it produces and if I get used to manual focus and often use it, is it really broken?  As long as the switch is on manual it's disengaged from the motor assembly, if that could present a problem in the future.

What purpose or condition of use is there is a manual mode option included? I don't know how fast USM autofocus is as i've never owned one. 

I have another 18 - 55 kit lens, from the shop, with broken plastic that i'm going to take apart to determine what skill level is required to reassemble without breaking any ribbon wires.

I'll ask some of the guys, that are uploading youtube videos on this repair, where or how they got replacement motors.

Thank you all for your replies. I appreciate it.

[Waddizzle]

I agree with Rick.  Using something that is electronically malfunctioning with functional gear is a risk.  It is not a risk that I would be inclined to make.

As far as repairing the lens goes, it is probably far less costly to purchase an EF 50mm f/1.8 STM than it might be to purchase whatever parts are needed to repair the f/1.4 lens and have them shipped to you.  

I’d sell the f/1.4 lens “for parts” on eBay, or somewhere, and buy a new or refurbished EF 50mm f/1.8.  I think they perform better than the f/1.4 lenses, anyway

[ebiggs1]

"I agree with Rick."  I do too but only 50%. I can't see any difference in a non-operative motor and turning the AF/MF switch to MF. But the 50%, if current is still getting to the motor I can see a possible problem so always make sure the switch is in the MF position.

[ROMzombi]

The motor assembly for the 50mm lens is available at Ebay for $99.99

Thank you for the information using flash to focus. 

[Waddizzle]

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@ROMzombi wrote:

The motor assembly for the 50mm lens is available at Ebay for $99.99

Thank you for the information using flash to focus. 

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EBay?  👎 Buyer Beware! 

You can buy a refurbished lens for the same price.  

https://www.usa.canon.com/shop/p/refurbished-ef-50mm-f-1-8-stm 

One year warranty.  The lens performs at least as well as the f/1.4, if not better.  I used to own the f/1.4.  It was soft wide open.  The AF motors were not very accurate.  They tended to undershoot or overshoot the mark.  I would almost not shoot wider than f/2.2, shooting at f/2.8 was typcial.

[ebiggs1]

I had no problems with my ef 50mm f1.4 in fact it was a very good lens but I totally agree the refurb is the way to go. Not even a choice. A cobbled 50mil or a guaranteed 50mil, hmmm?

I ended up selling my ef 50mm f1.4 and bought the Sigma 50mm f1.4 Art which eventually got sold in favor of the ef 50mm f1.2L which I dearly love.