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.

[jrhoffman75]

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@deebatman316 wrote:

What @5DIV is referring to is called an AF Assist Beam. Your semi dark room is too dark and lacks contrast for AF to work correctly. A DSLR camera relies on contrast not how bright something is. For instance the camera won't lock focus on a clear blue sky because it lacks contrast. The built in flash can provide quick strobe bursts of light to assist the camera's AF system. You can set to built in flash not to fire. Then have the built in flash providing AF Assist when the camera needs it. Some of Canon's speedlites project a red grid to assist the camera's AF system too. This method is faster and doesn't have any buzzing noises. Associated with Intermittent Flash Firing that the built in flash uses or some speedlites utilize.

AF Assist Beam projected from a speedlite. Note depending on how many AF points your camera has. The speedlite will project different AF Assist patterns.

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Won't help the OP's situation because he stated that the AF motor is broken.

[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.

[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.

[ebiggs1]

"The lens was from the leftover repairs that were abandoned, which was free."

And that tells you nothing? 🤔

[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.