EF-S 2x Teleconveter lens for Canon APS-C DSLR Cameras EF / EFS

Description

2X Teleconveter for Canon "
EF-S
" and "
EF
" mount
Available with or without white "EFS 2X" marking
Custom Built 2x Teleconverter
built by retrofitting, made in Japan, late film era, multicoated, full frame, teleconverter optics into Plastic Canon EF/EFS housing. All lens Electronics supported.
Design
:
Optics are set back a minimum of 10mm from the front flange to allow room for protruding back of EFS lenses.
Uses 2x teleconverters:
- double your lens's magnification  ( 250mm + 2x converter = 500mm )
- alternativly this teleconverter allows the use of crop sensor EFS lenses on frame EF camera. Image will fill entire sensor and have additional 1.4x magnification. ( EFS 250mm + 2x converter = EF 350mm )
Auto Focusing methods
with 2X teleconverter ranked fast to slow:
1 - [
0.15
sec ] Canon cameras  w/
Dual Pixel
AF
& Canon
STM
lens
2 - [
2.00
sec ] Canon cameras  w/
Dual Pixel
AF
& Canon
non STM
lens
3 - [
3.00
sec ] Canon cameras  w/
Hybrid CMOS AF
&  Canon
STM
lens
4 - [
4.00
sec ] Canon cameras  w/
Hybrid CMOS AF
& Canon
non STM
lens
5 - [
5+
sec ] Manual Focus
When using a teleconverter:
Use your camera's "Live View" mode for auto focus.
Modern Canon cameras are equipt with Dual Pixel CMOS AF. This is optimal for achieving Fastest AF speed.
a " Hoodman LCD Hoodloupe " is an accessory that sits over your cameras LCD screen, and can be used to add back Viewfinder functionality.
For sharpest pictures I recomend using a tripod or if handheld use iso 800 to achieve higher shutter speeds. For example when photographing hand held with a 250mm lens and 2x teleconverter, 1/250sec shutter speed, works well.
Optical Viewfinder, also known as TTL-SIR AF. Canon 9pt TTL-SIR AF requires f5.6, Canon 45pt TTL-SIR AF requires f8. Teleconverters reduce the amount of light entering the camera preventing optical viewfinder TTL- SIR AF from functioning unless the primary lens has a large aperature like f2.8
About the builder:
I am a mechanical engineer by trade, and I shoot wildlife photography and primarily use a Canon m100 and a Canon SL1
My favorite lens is the Canon "EF-S 55-250mm f4-5.6 IS STM" because it is a quality optic with great Image Stabilization.