EF-S mount was designed as an evolution of a standard, full-frame EF mount. EF-S lenses are optimized for crops sensors (APS-C), with the shorter back focus distance as the mirror in APS-C cameras is simply smaller. Thanks to this, it's possible to incorporate the lenses with shorter focal distances (10-18 or 10-22 mm, for example), to make physically smaller and lighter lenses.

1. Canon
EF-S Zooms lenses
April 2020

2. How EF-S differs from EF?
• EF-S, white dot, EF, red dot
• EF-S can not be fitted on EF
• EF can be fitted on EF-S
Consequently Canon
*(and all other manufacturers as well)
never really invested their efforts in developing
high-quality lenses for crop sensors

3. Math of APS-C
Full-frame
equivalent focal length
• 10 mm = 16 mm
• 15 mm = 24 mm
• 17 mm = 27 mm
• 18 mm = 29 mm
• 55 mm = 88 mm
• 85 mm = 136 mm
• 135 mm = 216 mm
• 200 mm = 320 mm
Full-frame
equivalent aperture
• f/2.8 = f/4.5
• f/3.5 = f/5.6
• f/4.0 = f/6.3
• f/4.5 = f/7.1
• f/5.6 = f/9.0
Just forget about the
bokeh

4. Wiiiiiide zooooom
7 blades aperture ֎
22 cm close focus
Ø 67 mm filter thread
240 g
150 EUR
6 blades ֎
24 cm
Ø 77 mm
385 g
200 EUR

5. Similar sharpness
10-18 mm has IS
and it’s 50 EUR cheaper

6. 7 blades ֎
35 cm
Ø 72 mm
575 g
250 EUR
The only 24 mm
equivalent choice
6 blades ֎
35 cm
Ø 67 mm
475 g
A lot with broken AF!
50 EUR

8. • 7 blades ֎
• 35 cm
• Ø 77 mm
• 645 g
• 250 EUR
The only available f/2.8 lens.
Keep in mind that on APS-C cameras,
f/2.8 = f/4.5 when it comes to bokeh

9. The only L-like lens

11. Non IS… IS… STM…
9/11 groups/elements
6 blades ֎
28 cm
Ø 58 mm
190 g
9/11 groups/elements
6 blades ֎
25 cm
Ø 58 mm
200 g
11/13 groups/elements
7 blades ֎
25 cm
Ø 58 mm
205 g

12. IS… IS II… STM…
basically the same

13. 12/16 groups/elements
6 blades ֎ 7 blades ֎ 7 blades ֎
45 cm 39 cm 39 cm
Ø 67 mm
455 g 480 g 515 g
130 EUR 150 EUR 150 EUR

14. The older one is a bit sharper,
but basically the same,
all in levels of experimental error

15. • 6 blades ֎
• 45 cm
• Ø 72 mm
• 595 g
Canon, 200-250 EUR
Tamron/Sigma 18-200 mm lenses
Can be found in 100-150 EUR range

16. 12/15 groups/elements
7 blades ֎
85 cm
Ø 58 mm
375 g
70 and 90 EUR
10/12
groups/elements
7 blades ֎
110 cm
Ø 58 mm
390 g
70 EUR
IS II

17. STM wins
The difference in price is very low,
thus STM is probably the best solution

18. Between 10-18 and 10-20, I would take 10-18, as it has IS.
3 Stops of IS sound better than 1 Stop of light,
while the difference between
18 mm (29 mm eq.) and 22 mm (35 mm eq.)
provides no real benefits from my point of view.
15-85 is the only option if you want to have 24 mm equivalent,
but the price tag is stepping into L-series domain.
The same is true for 17-55, f/2.8. The best lens money can buy,
and still, it can’t really compete with L-series and full frame.
17-85 could be a nice alternative to kit lenses, as the prices
drop to the same level. Keep in mind that there are many lenses
with a broken AF.
If you like travel-zooms, 18-135, avoid the first version,
as the price is basically the same, while the close focus is longer.
55-250, easy win for the newest STM model,
as the price for all three is basically the same

19. Thank you!
Have fun and make some
great photos
Find new toys,
and enhance your creativity
Share and Like, if you liked it…
There will be new presentations

20. References
• Canon Camera Museum:
https://global.canon/en/c-museum/
• DxoMark: https://www.dxomark.com/
• LeBonCoin for the prices: https://www.leboncoin.fr/
• A bit of Wiki and general Google images
• I apologize if I violated any copyrights, I find this to be
a fair use, very positive to Canon products and hopefully
useful for general public
Aleksandar Savic,
Phd in Physical Chemistry, April 2020