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Frequent Contributor
Posts: 64
Registered: ‎12-28-2019

Re: upgrade from the SL1 - T8i, 77D, SL3?

Thank you, Bob!
I would never had guessed this as an issue.. And I do use the pop up flash at times for fill flash.
Frequent Contributor
Posts: 64
Registered: ‎12-28-2019

Re: upgrade from the SL1 - T8i, 77D, SL3?

Ebiggs, I like that!
Can you somewhat easily set settings with the plastic over it?
I will check into the 90D when I get to the store Smiley Happy Thank you for all your help!
VIP
Posts: 13,584
Registered: ‎12-07-2012

Re: upgrade from the SL1 - T8i, 77D, SL3?

Yes, I leave the back of the bag open. Or if you prefer, you can completely seal it. It is easy to change settings.

EB
EOS 1DX and 1D Mk IV and several lenses!
Frequent Contributor
Posts: 64
Registered: ‎12-28-2019

Re: upgrade from the SL1 - T8i, 77D, SL3?

Thank you, Ebiggs!


I will try that sometime!!

And I exchanged my Sigma 17-50 F/2.8 for the Canon 17-55 F/2.8

It was odd, but I thought the Sigma let in about 1 - 2 less F-stops of light.  But it is a very good lens.

Annie

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Posts: 13,584
Registered: ‎12-07-2012

Re: upgrade from the SL1 - T8i, 77D, SL3?

"...I exchanged my Sigma 17-50 F/2.8 for the Canon 17-55 F/2.8"

 

Great! Smiley Happy The Canon is by far the better choice between those two.

 

"...I thought the Sigma let in about 1 - 2 less F-stops of light."

 

I doubt that but what caused you to believe so? There are two reasons why you might see this.  The Siggy might vignette more than the Canon.  It is easily corrected in post edit but a glance at an unprocessed image might appear that way.

 

Another reason is, beside the f-ratio, I.E. f2.8, lenses have a T ratio. That is transmission light through the lens.  Some lenses reflect light differently and loose or waste some light.  I don't know on the top of my head what the T ratio of the two lenses is but I bet the Canon is better.   Remember f ratio is a lens function.  It is a simple fraction equation of a concave or convex lens. And in this case, just piece of glass, not the entire package you think of when we say the word lens.

It has nothing to do with the camera.

 

 

EB
EOS 1DX and 1D Mk IV and several lenses!
VIP
Posts: 13,584
Registered: ‎12-07-2012

Re: upgrade from the SL1 - T8i, 77D, SL3?

"...I exchanged my Sigma 17-50 F/2.8 for the Canon 17-55 F/2.8"

 

Annie, 

The only Sigma lens in this range I an good with is the Sigma 18-35mm f/1.8 DC HSM Art Lens for Canon. Barring you buying this lens, stick with Canon lenses. This lens is absolutely fantastic and very fast.  Fastest in class. It has superb IQ also best in class. I used one on a 90D for a while and loved it. Hard to give it back.

EB
EOS 1DX and 1D Mk IV and several lenses!
Frequent Contributor
Posts: 64
Registered: ‎12-28-2019

Re: upgrade from the SL1 - T8i, 77D, SL3?

[ Edited ]

Ebiggs,

 

At the store, I did a comparison of the 2 lens outside (Sigma 17-50 F/2.8 vs Canon 17-55/F.28); it seemed like there was 1 one sep difference. But as you can say, it could have been anything.

 

I looked up the T Ratio (was not familiar with that before so thank you for mentioning!
The Sigma is actually a bit lower:

Canon: 3.4Tstop  

Sigma: 3.1Tstop  

 

[Removed 3rd party link per forum guidelines]


Interestingly, that comparison has the Sigma overall as the better lens, including for sharpness.
But I actually thought the Canon was sharper, probably why I should not pay too much attention to these  kinds of analyses.

All the best, Annie

VIP
Posts: 13,584
Registered: ‎12-07-2012

Re: upgrade from the SL1 - T8i, 77D, SL3?

"Interestingly, that comparison has the Sigma overall as the better lens, including for sharpness.
But I actually thought the Canon was sharper, probably why I should not pay too much attention to these  kinds of analyses."

 

I never go by the so called tests. That is why I took on the rather expensive hobby of lens testing on my own.  No lab, just real world use. One of the worst, IMHO, is DXO if that is where you read your data. 

 

Most of a time people judge a lens simply on one spec, IQ.  Everything else is not relevant. But in truth we all know a lens should be judged on it entirety. 

 

When you read the t ratio, remember it is also just one spec.  " I did a comparison of the 2 lens outside..." While I think this a good idea and one a lot of people don't do, it again isn't real conclusive, by itself. I did the same thing when I was buying my first 150-600mm super zoom.  Overland Camera, a local camera store, let me try it out outside. I wanted to see how the AF did before I bought one. What you should have done to complete your analysis of the two lenses in question, was to take the images you shot home and check them out in a good editor like PS. Like I said before a vignetted image can appear like it is down a 1/2 or full stop. When in fact it is not. It is an easy correction in post.

 

The f ratio is a round up or down. Usually down because the ad department has a say in it.  Sometimes a lens may factually be a f1.447 but the rounding it is stated as a f1.4. The same is true with FL. The actual FL may be 193mm but it gets rounded to 200mm.  All of this has to be considered and the lens taken as a package and not just one spec. Make sense?

EB
EOS 1DX and 1D Mk IV and several lenses!
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