Canon EF Mount lens on a 645??

nathanduncanphoto · 09-03-2017, 11:13 PM

Is this possible? I've been heavily invested in Canon EOS gear for a long time and shoot the 6D. Before you all laugh at what maybe a silly question :-D..... I'm a really recent 645 owner and I have the 80-160mm lens and....c'mon, it's a tank! I really wanted to enter the medium format world and the original 645 was my first fiscally responsible choice. I'm looking for something more mobile. I don't care about losing f/ function if that's the case. I mean, if it's a cheap adapter, I'll go for it just to experiment. All the adapters I've seen out there are for 645 lenses to 35mm fullframe bodies, but not the visa versa. Thoughts?

**clackers** · 09-03-2017, 11:24 PM

Nathan, Canon have never made medium format, so for starters I can't see any of their lenses covering a big sensor like the one on your 645 ...

**seventhdr** · 09-03-2017, 11:32 PM - **1 Like**

Short answer. NO.

The distance from the flange of the lens mount to the sensor plane is the important distance. Lenses designed for a camera with a longer flange to sensor distance can be mounted on a camera with a shorter flange to sensor distance by using an adapter to make up the difference between the two flange to sensor dimensions. So you can mount Pentax 67 lenses on 645, 645 lenses on Pentax K-mount or lenses on Canon EF mount. There are adapters for all these combinations.

Canon EF lenses have a shorter flange to sensor distance than 645 cameras. This would mean that the flange of the lens would have to be INSIDE the 645 lens mount to allow correct focusing. This is something that just would NOT work. You could construct an adapter with additional glass to correct for this situation, but no one makes them.

Regards

Chris

surfar · 09-04-2017, 12:06 AM

Your Canon glass can be mounted on the ML Fuji,plenty of dumb adapters and a recently anounced AF one by TechArt Pro.

**clackers** · 09-04-2017, 03:38 AM - **1 Like**

Originally posted by surfar

Your Canon glass can be mounted on the ML Fuji,plenty of dumb adapters and a recently anounced AF one by TechArt Pro.

Don't do this, they'll need corrective glass!

672 · 09-04-2017, 09:27 PM

actually there are a number of canon lenses that will cover a 44mm image circle quite comfortably.

**clackers** · 09-04-2017, 09:36 PM

Originally posted by 672

actually there are a number of canon lenses that will cover a 44mm image circle quite comfortably.

What were you thinking of, 672?

The OP has a 6D, so he probably has EF lenses.

nathanduncanphoto · 09-05-2017, 10:42 PM

Originally posted by clackers

Nathan, Canon have never made medium format, so for starters I can't see any of their lenses covering a big sensor like the one on your 645 ...

Thanks clackers. I should've mentioned that my 645 is the original film version. Not sure if that makes a difference though - for mounting an EF lens on that body.

**clackers** · 09-05-2017, 10:46 PM

Originally posted by nathanduncanphoto

Thanks clackers. I should've mentioned that my 645 is the original film version. Not sure if that makes a difference though - for mounting an EF lens on that body.

It makes it worse, Nathan, because it will really be 6cmx4.5cm, right?

As I understand it, the 645D and 645Z use cropped MF sensors, about two-thirds the size.

nathanduncanphoto · 09-05-2017, 10:47 PM

Originally posted by seventhdr

Short answer. NO.

The distance from the flange of the lens mount to the sensor plane is the important distance. Lenses designed for a camera with a longer flange to sensor distance can be mounted on a camera with a shorter flange to sensor distance by using an adapter to make up the difference between the two flange to sensor dimensions. So you can mount Pentax 67 lenses on 645, 645 lenses on Pentax K-mount or lenses on Canon EF mount. There are adapters for all these combinations.

Canon EF lenses have a shorter flange to sensor distance than 645 cameras. This would mean that the flange of the lens would have to be INSIDE the 645 lens mount to allow correct focusing. This is something that just would NOT work. You could construct an adapter with additional glass to correct for this situation, but no one makes them.

Regards

Chris

Thanks seventhdr1. I should've mentioned that my 645 is the original film version. Not sure if that makes a difference though - for mounting an EF lens on that body. Makes sense what you said though. That corrective glass on other ones makes a difference (like Canon FD to EF mount, etc).

---------- Post added 09-05-17 at 10:50 PM ----------

Originally posted by clackers

It makes it worse, Nathan, because it will really be 6cmx4.5cm, right?

As I understand it, the 645D and 645Z use cropped MF sensors, about two-thirds the size.

True true, I was thinking that just now. The D and Z sensors are considerably smaller than the 645 film image.

---------- Post added 09-05-17 at 10:52 PM ----------

Thanks everyone! Looks like I'll have to look at medium format options going forward.

**baro-nite** · 09-06-2017, 12:52 PM - **1 Like**

Some of the Pentax 645 lenses are excellent value and also quite compact. A150 is quite compact for such a long focal length, and IMO a great value (one of my most used lenses). Has a built-in hood. The 75 (either the A or the FA) is very compact for a MF lens, also a great performer, more expensive than the 150 but still a pretty good value. The A55 is also good, and not too large and a pretty good value.

Pablo Villegas · 09-06-2017, 05:40 PM - **1 Like**

645 A lenses are very cheap, and most primes are not that heavy or big, the zooms are another story.

nathanduncanphoto · 09-07-2017, 07:08 PM

Originally posted by baro-nite

Some of the Pentax 645 lenses are excellent value and also quite compact. A150 is quite compact for such a long focal length, and IMO a great value (one of my most used lenses). Has a built-in hood. The 75 (either the A or the FA) is very compact for a MF lens, also a great performer, more expensive than the 150 but still a pretty good value. The A55 is also good, and not too large and a pretty good value.

Ya I was looking at the 55 or the 75 recently. I like those.

---------- Post added 09-07-17 at 07:10 PM ----------

Originally posted by Pablo Villegas

645 A lenses are very cheap, and most primes are not that heavy or big, the zooms are another story.

I agree with you. I was just trying to be cheap and use my current stuff if possible. But the Pentax-A 55mm & 75mm are rather great values and light.

672 · 09-11-2017, 08:59 PM

Originally posted by clackers

What were you thinking of, 672?

The OP has a 6D, so he probably has EF lenses.

i was stirring the pot a little bit. i know the OP wants to use his canon glass on pentax 645 AND his canon FF. not possible. my point was more that many canon lenses do in fact have an image circle that covers a 44mm circle. i have a canon FD 600mm f4.5 that i shoot on pentax 645Z. it was at some point chopped up for cinema use and covers 44mm quite comfortably.

**clackers** · 09-12-2017, 01:34 PM

Originally posted by 672

i was stirring the pot a little bit. i know the OP wants to use his canon glass on pentax 645 AND his canon FF. not possible. my point was more that many canon lenses do in fact have an image circle that covers a 44mm circle. i have a canon FD 600mm f4.5 that i shoot on pentax 645Z. it was at some point chopped up for cinema use and covers 44mm quite comfortably.

Being all manual it probably works fine for you, 672.

Don't know how he'd even have a working aperture with an EF lens.

09-03-2017, 11:13 PM	#1
nathanduncanphoto New Member Join Date: Aug 2017 Location: Arkansas Posts: 15	Canon EF Mount lens on a 645?? Is this possible? I've been heavily invested in Canon EOS gear for a long time and shoot the 6D. Before you all laugh at what maybe a silly question :-D..... I'm a really recent 645 owner and I have the 80-160mm lens and....c'mon, it's a tank! I really wanted to enter the medium format world and the original 645 was my first fiscally responsible choice. I'm looking for something more mobile. I don't care about losing f/ function if that's the case. I mean, if it's a cheap adapter, I'll go for it just to experiment. All the adapters I've seen out there are for 645 lenses to 35mm fullframe bodies, but not the visa versa. Thoughts?

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
For Sale - Sold: Canon EF 70-300mm f/4-5.6 IS USM, EF-S 60mm f/2.8 Macro USM (price reduced)	beachgardener	Sold Items	3	10-11-2014 02:55 PM
For Sale - Sold: Canon 40D with Canon EF-S 18-55 IS Lens + goodies!	johnwdavisjr	Sold Items	6	02-21-2014 02:47 PM
Pentax 645 - Canon EF/EF-S Adapter	derAngler	Pentax Medium Format	9	07-07-2013 11:07 AM
For Sale - Sold: Canon EOS 500D/T1i Camera + Canon Zoom Lens EF-S 18-55mm 1:3.5-5.6 IS	mackloon	Sold Items	7	08-13-2011 10:58 AM

09-03-2017, 11:24 PM	#2
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Nathan, Canon have never made medium format, so for starters I can't see any of their lenses covering a big sensor like the one on your 645 ...

09-03-2017, 11:32 PM - 1 Like	#3
seventhdr Site Supporter Join Date: Mar 2007 Location: Christchurch, New Zealand Photos: Gallery Posts: 1,439	Short answer. NO. The distance from the flange of the lens mount to the sensor plane is the important distance. Lenses designed for a camera with a longer flange to sensor distance can be mounted on a camera with a shorter flange to sensor distance by using an adapter to make up the difference between the two flange to sensor dimensions. So you can mount Pentax 67 lenses on 645, 645 lenses on Pentax K-mount or lenses on Canon EF mount. There are adapters for all these combinations. Canon EF lenses have a shorter flange to sensor distance than 645 cameras. This would mean that the flange of the lens would have to be INSIDE the 645 lens mount to allow correct focusing. This is something that just would NOT work. You could construct an adapter with additional glass to correct for this situation, but no one makes them. Regards Chris

09-04-2017, 12:06 AM	#4
surfar Pentaxian Join Date: Jan 2015 Location: mid nth coast,nsw Photos: Gallery Posts: 6,137	Your Canon glass can be mounted on the ML Fuji,plenty of dumb adapters and a recently anounced AF one by TechArt Pro.

09-04-2017, 03:38 AM - 1 Like	#5
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Originally posted by surfar Your Canon glass can be mounted on the ML Fuji,plenty of dumb adapters and a recently anounced AF one by TechArt Pro. Don't do this, they'll need corrective glass!

09-04-2017, 09:27 PM	#6
672 Veteran Member Join Date: Dec 2010 Location: santa monica Photos: Gallery Posts: 486	actually there are a number of canon lenses that will cover a 44mm image circle quite comfortably.

09-04-2017, 09:36 PM	#7
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Originally posted by 672 actually there are a number of canon lenses that will cover a 44mm image circle quite comfortably. What were you thinking of, 672? The OP has a 6D, so he probably has EF lenses.

09-05-2017, 10:42 PM	#8
nathanduncanphoto New Member Join Date: Aug 2017 Location: Arkansas Posts: 15 Original Poster	Originally posted by clackers Nathan, Canon have never made medium format, so for starters I can't see any of their lenses covering a big sensor like the one on your 645 ... Thanks clackers. I should've mentioned that my 645 is the original film version. Not sure if that makes a difference though - for mounting an EF lens on that body.

09-05-2017, 10:46 PM	#9
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Originally posted by nathanduncanphoto Thanks clackers. I should've mentioned that my 645 is the original film version. Not sure if that makes a difference though - for mounting an EF lens on that body. It makes it worse, Nathan, because it will really be 6cmx4.5cm, right? As I understand it, the 645D and 645Z use cropped MF sensors, about two-thirds the size.

09-05-2017, 10:47 PM	#10
nathanduncanphoto New Member Join Date: Aug 2017 Location: Arkansas Posts: 15 Original Poster	Originally posted by seventhdr Short answer. NO. The distance from the flange of the lens mount to the sensor plane is the important distance. Lenses designed for a camera with a longer flange to sensor distance can be mounted on a camera with a shorter flange to sensor distance by using an adapter to make up the difference between the two flange to sensor dimensions. So you can mount Pentax 67 lenses on 645, 645 lenses on Pentax K-mount or lenses on Canon EF mount. There are adapters for all these combinations. Canon EF lenses have a shorter flange to sensor distance than 645 cameras. This would mean that the flange of the lens would have to be INSIDE the 645 lens mount to allow correct focusing. This is something that just would NOT work. You could construct an adapter with additional glass to correct for this situation, but no one makes them. Regards Chris Thanks seventhdr1. I should've mentioned that my 645 is the original film version. Not sure if that makes a difference though - for mounting an EF lens on that body. Makes sense what you said though. That corrective glass on other ones makes a difference (like Canon FD to EF mount, etc). ---------- Post added 09-05-17 at 10:50 PM ---------- Originally posted by clackers It makes it worse, Nathan, because it will really be 6cmx4.5cm, right? As I understand it, the 645D and 645Z use cropped MF sensors, about two-thirds the size. True true, I was thinking that just now. The D and Z sensors are considerably smaller than the 645 film image. ---------- Post added 09-05-17 at 10:52 PM ---------- Thanks everyone! Looks like I'll have to look at medium format options going forward.

09-06-2017, 12:52 PM - 1 Like	#11
baro-nite Loyal Site Supporter Join Date: Aug 2011 Location: North Carolina, USA Photos: Gallery \| Albums Posts: 5,294	Some of the Pentax 645 lenses are excellent value and also quite compact. A150 is quite compact for such a long focal length, and IMO a great value (one of my most used lenses). Has a built-in hood. The 75 (either the A or the FA) is very compact for a MF lens, also a great performer, more expensive than the 150 but still a pretty good value. The A55 is also good, and not too large and a pretty good value.

Thread Tools	Search this Thread
	Search this Thread: Advanced Search

09-06-2017, 05:40 PM - 1 Like	#12
Pablo Villegas Senior Member Join Date: Sep 2016 Posts: 158	645 A lenses are very cheap, and most primes are not that heavy or big, the zooms are another story.

09-07-2017, 07:08 PM	#13
nathanduncanphoto New Member Join Date: Aug 2017 Location: Arkansas Posts: 15 Original Poster	Originally posted by baro-nite Some of the Pentax 645 lenses are excellent value and also quite compact. A150 is quite compact for such a long focal length, and IMO a great value (one of my most used lenses). Has a built-in hood. The 75 (either the A or the FA) is very compact for a MF lens, also a great performer, more expensive than the 150 but still a pretty good value. The A55 is also good, and not too large and a pretty good value. Ya I was looking at the 55 or the 75 recently. I like those. ---------- Post added 09-07-17 at 07:10 PM ---------- Originally posted by Pablo Villegas 645 A lenses are very cheap, and most primes are not that heavy or big, the zooms are another story. I agree with you. I was just trying to be cheap and use my current stuff if possible. But the Pentax-A 55mm & 75mm are rather great values and light.

09-11-2017, 08:59 PM	#14
672 Veteran Member Join Date: Dec 2010 Location: santa monica Photos: Gallery Posts: 486	Originally posted by clackers What were you thinking of, 672? The OP has a 6D, so he probably has EF lenses. i was stirring the pot a little bit. i know the OP wants to use his canon glass on pentax 645 AND his canon FF. not possible. my point was more that many canon lenses do in fact have an image circle that covers a 44mm circle. i have a canon FD 600mm f4.5 that i shoot on pentax 645Z. it was at some point chopped up for cinema use and covers 44mm quite comfortably.

09-12-2017, 01:34 PM	#15
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Originally posted by 672 i was stirring the pot a little bit. i know the OP wants to use his canon glass on pentax 645 AND his canon FF. not possible. my point was more that many canon lenses do in fact have an image circle that covers a 44mm circle. i have a canon FD 600mm f4.5 that i shoot on pentax 645Z. it was at some point chopped up for cinema use and covers 44mm quite comfortably. Being all manual it probably works fine for you, 672. Don't know how he'd even have a working aperture with an EF lens.