Minimum Focusing Distance Question

[Kenny101]

Newbie to the Camera world so thanks for the great info. I bought a Canon 50mm F/1.8 for portraits based on other chats and very happy with it, but I am curious to understatnd why I have to stand further away then for the F/1.4. Probably very basic, but I'm still trying to understand the relationships amongst all the different "parts of the photo". 

[ebiggs1]

"I bought a Canon 50mm F/1.8 for portraits ..."

I don't understand your question?  You already had a 50mm f1.4 and bought a 50mm f1.8? What each shows the camera will be exactly the same. The only difference is a small difference in DOF when using f1.4 compared to f1.8. Very small difference.

Are you comparing the two 50mm lenses on the same camera?  If one camera is a FF and the other a cropper, there will be a significant difference between the two. It isn't that they have different f-stops. The 50mm on a cropper would equate to an 80mm.

[Kenny101]

sorry for the confusion. I already bought a 1.8, but I started reading that the 1.4 was so much better and worth the extra money. From what I can research today, it appears that the difference is quite small and the average hack like myself would never see the difference. 

[TCampbell]

You shouldn't need to... 

Minimum focus distance for the 50mm f/1.4 is 1.5' 

Minimum focus distance for the 50mm f/1.8 is 1.15'

(that's measured from the sensor... not the lens.  There's a focus-mark on the top of the camera that looks like an "O" with a horizontal line drawn through it... it marks the sensor position.)

The 50mm f/1.8 II and the 50mm f/1.8 STM have identical optics (Canon didn't change the glass).  They changed the focus motor and the aperture blades (the STM lens have more aperture blades produces a better quality of blur.)

Every lens model will have a different minimum focus distance because the optical formula (choice of lens elements and their configuration) will be different to achieve the results the engineers want.

If you want to be able to get much closer (e.g. makeup photography), then consider getting a macro lens such as the EF-S 60mm f/2.8 Macro USM (if using an APS-C sensor camera) or the EF 100mm f/2.8 Macro USM (there is also an "L" series version of the 100mm macro that has image stabililzation)  if using a full-frame sensor camera.  These lenses can achieve focus at extremely close distance and are designed to provide 1:1 scale magnification.  1:1 means that the size of the image projected onto the sensor is as large as the subject is in real life.   If using an APS-C sensor camera... a photo of a penny could fill the frame.

[kvbarkley]

At standard portrait distances, with each lens in its autofocus range, *all* 50 mm lenses should have the same image size on the same camera.

Something does not make sense in your description.

[MikeSowsun]

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@Kenny101 wrote:

Newbie to the Camera world so thanks for the great info. I bought a Canon 50mm F/1.8 for portraits based on other chats and very happy with it, but I am curious to understatnd why I have to stand further away then for the F/1.4. Probably very basic, but I'm still trying to understand the relationships amongst all the different "parts of the photo". 

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What makes you think you have to stand farther away when using the 50mm f1.8 ?

Is it something you read about? Or have you compared these two lenses side by side?

[Kenny101]

Thanks Mike. I was reading the thread on question 

Please recommend lens for portraits

 and I came across this in a reply

I agree with Ciccopo. 50mm is probably the best length for portraits on a crop sensor. And the f/1.4 version is probably the best choice at around your budget.

You could also go for the Canon 85mm f/1.8, but you would need rom to stand back a bit with a crop body, and you would tend to get tighter head or head and shoulders only shots.

Before I also invested in a 1.4, I wanted to find out if it is worth it and from what I can gather, it is not worth it for the non-professional. 

[MikeSowsun · Accepted solution]

The Canon EF 50mm f/1.8 STM lens is a great lens and is great value for the money.

I would not recommend the EF 50mm f/1.4 USM for the average user because the negative factors (higher cost, poor AF motor reliability) outweigh any positive factors.

[Kenny101]

Thank you all for your immediate responses.

[ebiggs1]

"The Canon EF 50mm f/1.8 STM lens is a great lens and is great value for the money."

And, the appeal of the f1.8 STM lens ends with the low cost. If you discount the price factor, which I already gave in to, the f1.4 is the better lens package. I used two of them for years and when I say I used them, they got used. Daily, with no malfunctions. There is a reason the f1.8 is cheaper don't forget that. It is more plasticiky and the f1.4 is more metalish. So better build goes to the f1.4. It does have the slightly wider aperture which among other things has better bokeh. Need to shoot at f1.4, oh, wait the f1.8 doesn't have that. MF is also better on the f1.4.

Bottom line they are both sharp and work well. If money is your main most concern, that by all means buy the f1.8. However, if you can drop the dime get the f1.4.

In my case I bought the fantastic 50mm f1.2L which blows any other 50mil out of the water!