Canon 7D Mark II - DXOMark Review

[East Wind Photography]

however how much do you think having the stock IR filter still in the camera is holding you back. I could be wrong but aren't you getting around 2-3 stop attenuation there? especially in nebulosity? I know canon's pretty extreme now (if you've ever tried taking IR photos with a R72,etc)

Oh absolutely, the IR cut filter in DSLRs kills off a ton of the Hydrogen-alpha light. My red channel lags my green and blue channels by at least a couple stops, and as such it is always noisier. There are mods out there, from Baader and from Astrodon, where you can pull out the LPF filters in Canon cameras and replace them with astro-geared IR/UV cutoff filters that have a square cutoff, rather than a gradual rolloff into the reds. That can improve Ha and SII transmission from around 20% to around 90% (Baader) or 99% (Astrodon). The problem with these mods is they make regular photography more difficult. You can use custom WB settings, but there is always a strong red hue, and it is very difficult to get rid of.

yes, I do infrared photography, so what I tend to do is get a full or dual spectrum converted camera (a UV block only) and then use filters in front.

thus the camera still works as a terrestrial camera and also as an astro imager.

but you are right - nothing will beat a dedicated CCD imager and the inclusion of the consistent cooling if you are serious about the craft.

looks like where you are, you are in a pretty good area for it to as well - I look at your images and my fingers start twitch to get back into it seriously - however living in a downtown city core isn't' exactly a good location for serious work.

I live in a red/orange zone (depends on the night)...the LP is pretty bad here. Far from a great area for AP though. I do some unfiltered imaging, on brighter targets. I filter all the rest, as it is pretty essential. I am actually looking to sell the Astronomik CLS-XL and get a 52mm screw-in for my drop-in filter on my 600mm lens. I'm going to be getting the IDAS, probably the LPS-D1, although I may pick up the LPS-P2 instead (if I can find it.) The IDAS filters are a little more tuned, and block narrower bands while passing the rest, so color balance is a bit easier (and they don't cut out as much light, so you don't necessarily have to expose for as long.)

have you looked at the QHYCCD?

I have. I've also looked at Atik. I own the QHY5L-II guide and planetary camera, which uses an Aptina sensor. I checked out the larger QHY cameras. Their full-frame 11002 camera is actually probably one of the best priced out there...however I've heard a number of times about fogging/frosting problems with the QHY design, and I have never really heard much about their noise quality. QHY and FLI both put a lot of effort into ensuring non-patterned read noise, which is essential for AP as we average many frames together. Any pattern, instead of getting averaged out, ends up getting strengthened like any other signal.

The problem with screw ins on the Canon lenses are that they need to be low profile filters. Most AP filter makers dont offer low profile rings so it's a crap shoot. I ended up just buying extra drop in UV filters and ordering standard 2" AP filters. The filters drop right in place of the UV glass with the addition of some shims (electrical tape) to accomodate the thinner glass used by some manufacturers. I use them both on my 300 and 600 and work quite well. The only draw back is that you cant easily use them for other purposes. However, I think its worth it just to have dedicated filters for use in the lenses rather that dealing with threading them in the field. Less time fiddling means more time actually shooting.

 

[jrista]

The problem with screw ins on the Canon lenses are that they need to be low profile filters. Most AP filter makers dont offer low profile rings so it's a crap shoot. I ended up just buying extra drop in UV filters and ordering standard 2" AP filters. The filters drop right in place of the UV glass with the addition of some shims (electrical tape) to accomodate the thinner glass used by some manufacturers. I use them both on my 300 and 600 and work quite well. The only draw back is that you cant easily use them for other purposes. However, I think its worth it just to have dedicated filters for use in the lenses rather that dealing with threading them in the field. Less time fiddling means more time actually shooting.

Yeah, the IDAS filters I am looking at are 7mm thick, and the Canon drop-in filter holder needs 5mm thick. I was planning on just lapping the filter ring.


However, if I understand you correctly, your solution was to get 52mm slim UV filters, remove the UV glass and drop in the LP filter? I hadn't thought of that...but it's a damn good idea. What UV filters do you use?

 

[East Wind Photography]

The problem with screw ins on the Canon lenses are that they need to be low profile filters. Most AP filter makers dont offer low profile rings so it's a crap shoot. I ended up just buying extra drop in UV filters and ordering standard 2" AP filters. The filters drop right in place of the UV glass with the addition of some shims (electrical tape) to accomodate the thinner glass used by some manufacturers. I use them both on my 300 and 600 and work quite well. The only draw back is that you cant easily use them for other purposes. However, I think its worth it just to have dedicated filters for use in the lenses rather that dealing with threading them in the field. Less time fiddling means more time actually shooting.

Yeah, the IDAS filters I am looking at are 7mm thick, and the Canon drop-in filter holder needs 5mm thick. I was planning on just lapping the filter ring.


However, if I understand you correctly, your solution was to get 52mm slim UV filters, remove the UV glass and drop in the LP filter? I hadn't thought of that...but it's a damn good idea. What UV filters do you use?

No its actually easier than that. I ordered the Canon standard drop in UV filter...same as the one that comes with the lens. Just gingerly swap out the glass.

 

[jrista]

The problem with screw ins on the Canon lenses are that they need to be low profile filters. Most AP filter makers dont offer low profile rings so it's a crap shoot. I ended up just buying extra drop in UV filters and ordering standard 2" AP filters. The filters drop right in place of the UV glass with the addition of some shims (electrical tape) to accomodate the thinner glass used by some manufacturers. I use them both on my 300 and 600 and work quite well. The only draw back is that you cant easily use them for other purposes. However, I think its worth it just to have dedicated filters for use in the lenses rather that dealing with threading them in the field. Less time fiddling means more time actually shooting.

Yeah, the IDAS filters I am looking at are 7mm thick, and the Canon drop-in filter holder needs 5mm thick. I was planning on just lapping the filter ring.


However, if I understand you correctly, your solution was to get 52mm slim UV filters, remove the UV glass and drop in the LP filter? I hadn't thought of that...but it's a damn good idea. What UV filters do you use?

No its actually easier than that. I ordered the Canon standard drop in UV filter...same as the one that comes with the lens. Just gingerly swap out the glass.

Hmm, I'm not sure what exactly is different about that. I already ordered this:


http://www.bhphotovideo.com/c/product/763737-REG/Canon_4773B001_52mm_Drop_in_Gelatin_Filter.html


This, the drop-in CLP, and the gel holder (which came with the lens) are the only options available for the 600/4 II. It does not appear that this has a UV filter in it...it's just a drop-in for 52mm screw-in filters.

 

[East Wind Photography]

The problem with screw ins on the Canon lenses are that they need to be low profile filters. Most AP filter makers dont offer low profile rings so it's a crap shoot. I ended up just buying extra drop in UV filters and ordering standard 2" AP filters. The filters drop right in place of the UV glass with the addition of some shims (electrical tape) to accomodate the thinner glass used by some manufacturers. I use them both on my 300 and 600 and work quite well. The only draw back is that you cant easily use them for other purposes. However, I think its worth it just to have dedicated filters for use in the lenses rather that dealing with threading them in the field. Less time fiddling means more time actually shooting.

Yeah, the IDAS filters I am looking at are 7mm thick, and the Canon drop-in filter holder needs 5mm thick. I was planning on just lapping the filter ring.


However, if I understand you correctly, your solution was to get 52mm slim UV filters, remove the UV glass and drop in the LP filter? I hadn't thought of that...but it's a damn good idea. What UV filters do you use?

No its actually easier than that. I ordered the Canon standard drop in UV filter...same as the one that comes with the lens. Just gingerly swap out the glass.

Hmm, I'm not sure what exactly is different about that. I already ordered this:


http://www.bhphotovideo.com/c/product/763737-REG/Canon_4773B001_52mm_Drop_in_Gelatin_Filter.html


This, the drop-in CLP, and the gel holder (which came with the lens) are the only options available for the 600/4 II. It does not appear that this has a UV filter in it...it's just a drop-in for 52mm screw-in filters.

Hmmm I have the 600 mk1 and the gel holder w/glass UV works fine. I see the gel holder on BandH says for the 300 and 400mm but doesnt mention the 600. I bet it would work in the 600 Mk II.

The gel holder also has a glasss UV filter but has to be removed by removing a clip that holds it in.

 

[Loswr]

The gel holder also has a glasss UV filter but has to be removed by removing a clip that holds it in.

I wasn't aware the piece of glass in the drop-in gel holder that comes with the superteles was specifically a UV filter – I thought it was just optical glass.

 

[East Wind Photography]

The gel holder also has a glasss UV filter but has to be removed by removing a clip that holds it in.

I wasn't aware the piece of glass in the drop-in gel holder that comes with the superteles was specifically a UV filter – I thought it was just optical glass.

Yes I think you are right about that. However in this case we are just discarding the glass and using the AP filter in its place. According to the 600 mk II manual any of the 52w(II) drop in filters will work. You can use non II drop ins but the color would be the old mk I color.

I would recommend using the gel holder instead of the screw on type with AP 2" filter glass 48mm? I don't believe the 52mm glass will fit...though it might. I would have to measure the glass that was removed.

 

[Loswr]

The gel holder also has a glasss UV filter but has to be removed by removing a clip that holds it in.

I wasn't aware the piece of glass in the drop-in gel holder that comes with the superteles was specifically a UV filter – I thought it was just optical glass.

Yes I think you are right about that. However in this case we are just discarding the glass and using the AP filter in its place. According to the 600 mk II manual any of the 52w(II) drop in filters will work. You can use non II drop ins but the color would be the old mk I color.

I would recommend using the gel holder instead of the screw on type with AP 2" filter glass 48mm? I don't believe the 52mm glass will fit...though it might. I would have to measure the glass that was removed.

Understood. I (possibly jrista, too) thought you were talking about buying a slim-mount (<5mm) 52mm screw-in UV filter (something cheap, Tiffen/Promaster/etc.,), opening up the mount, then replacing the UV filter glass with the LP filter glass removed from their thick mount.

 

[jrista]

The gel holder also has a glasss UV filter but has to be removed by removing a clip that holds it in.

I wasn't aware the piece of glass in the drop-in gel holder that comes with the superteles was specifically a UV filter – I thought it was just optical glass.

Yes I think you are right about that. However in this case we are just discarding the glass and using the AP filter in its place. According to the 600 mk II manual any of the 52w(II) drop in filters will work. You can use non II drop ins but the color would be the old mk I color.

I would recommend using the gel holder instead of the screw on type with AP 2" filter glass 48mm? I don't believe the 52mm glass will fit...though it might. I would have to measure the glass that was removed.

Understood. I (possibly jrista, too) thought you were talking about buying a slim-mount (<5mm) 52mm screw-in UV filter (something cheap, Tiffen/Promaster/etc.,), opening up the mount, then replacing the UV filter glass with the LP filter glass removed from their thick mount.

This was my original understanding. I think it would work...however, i cannot tell if slim UV filters are manufactured to be taken apart or not. They are also fairly expensive.


I'll have to see about disassembling the gel drop-in...I've examined it before, I did not notice a way to remove the glass. In mine, I think there are two pieces of glass, between which the gels are sandwiched.

 

[East Wind Photography]

The gel holder also has a glasss UV filter but has to be removed by removing a clip that holds it in.

I wasn't aware the piece of glass in the drop-in gel holder that comes with the superteles was specifically a UV filter – I thought it was just optical glass.

Yes I think you are right about that. However in this case we are just discarding the glass and using the AP filter in its place. According to the 600 mk II manual any of the 52w(II) drop in filters will work. You can use non II drop ins but the color would be the old mk I color.

I would recommend using the gel holder instead of the screw on type with AP 2" filter glass 48mm? I don't believe the 52mm glass will fit...though it might. I would have to measure the glass that was removed.

Understood. I (possibly jrista, too) thought you were talking about buying a slim-mount (<5mm) 52mm screw-in UV filter (something cheap, Tiffen/Promaster/etc.,), opening up the mount, then replacing the UV filter glass with the LP filter glass removed from their thick mount.

This was my original understanding. I think it would work...however, i cannot tell if slim UV filters are manufactured to be taken apart or not. They are also fairly expensive.


I'll have to see about disassembling the gel drop-in...I've examined it before, I did not notice a way to remove the glass. In mine, I think there are two pieces of glass, between which the gels are sandwiched.

It's been over a year since I did it. There was only one piece of glass. If I recall correctly there is a ring that keeps the glass in position. I just dont recall if it needs to be compressed or if there are screws to remove. However I did do it with my lumicon filters and I recall that it was easy. The hard part was removing the AP filter from the 2" ring without damaging the filter.

I also have one of those screw type drop ins and I remember that the glass filter it came with was a bear to get off the drop in part. I believe I had to use channel locks and hot water.

 

[scyrene]

I'm glad I'm not the only one who's looked at this. I've not tried the Astronomik full frame in-body filters yet though, and until I get a tracking mount that will take the big lens, it's not a priority. Let us know if it's possible to modify the drop in filters!

 

[jrista]

I'm glad I'm not the only one who's looked at this. I've not tried the Astronomik full frame in-body filters yet though, and until I get a tracking mount that will take the big lens, it's not a priority. Let us know if it's possible to modify the drop in filters!

Will do.


Regarding the Astronomik filters. My problem is specifically with the CLS-XL clip-in for the Canon FF DSLRs. I have two Astronomik CLS filters, as I also have the one for APS-C. I think the design of the APS-C one, the "CLS" is far better. It only fits in one way (the CLS-XL can be reversed, which can cause problems with vignetting as the vignette the filter frame causes is not uniform....I marked one of the tabs on the sides of mine with a silver dot so I knew which direction to put it in), it fits inside the camera without messing with the mirror, and it does not allow any light leak around the edges.


The CLS-XL has problems with non-uniform vignette, it has a large frame that wraps around to hold onto the filter, which effectively reduces the non-vignetted viewport to the sensor, it does NOT fit in the camera without locking up the mirror, it does not fill the entire space when the mirror is lifted up, and it moves around as the mirror moves up and down in the 1-2mm gap above the filter.


Basically, the CLS-XL is just a disastrous design, it was poorly thought out and hacked together. I don't really recommend it for anyone. Hence the reason I am looking into an IDAS screw-in. The IDAS filters are multi-bandpass, blocking only the key bands where primary LP sources (sodium and mercury vapor lamps) emit light. It passes a broader spectrum, so is easier to color correct as well. Since the IDAS will fit into the lens filter holder (in some fashion, I'm going to try EWP's trick) it can be used on any camera I attach to the lens, so I may just sell both my Astronomik filters.

 

[scyrene]

I'm glad I'm not the only one who's looked at this. I've not tried the Astronomik full frame in-body filters yet though, and until I get a tracking mount that will take the big lens, it's not a priority. Let us know if it's possible to modify the drop in filters!

Will do.


Regarding the Astronomik filters. My problem is specifically with the CLS-XL clip-in for the Canon FF DSLRs. I have two Astronomik CLS filters, as I also have the one for APS-C. I think the design of the APS-C one, the "CLS" is far better. It only fits in one way (the CLS-XL can be reversed, which can cause problems with vignetting as the vignette the filter frame causes is not uniform....I marked one of the tabs on the sides of mine with a silver dot so I knew which direction to put it in), it fits inside the camera without messing with the mirror, and it does not allow any light leak around the edges.


The CLS-XL has problems with non-uniform vignette, it has a large frame that wraps around to hold onto the filter, which effectively reduces the non-vignetted viewport to the sensor, it does NOT fit in the camera without locking up the mirror, it does not fill the entire space when the mirror is lifted up, and it moves around as the mirror moves up and down in the 1-2mm gap above the filter.


Basically, the CLS-XL is just a disastrous design, it was poorly thought out and hacked together. I don't really recommend it for anyone. Hence the reason I am looking into an IDAS screw-in. The IDAS filters are multi-bandpass, blocking only the key bands where primary LP sources (sodium and mercury vapor lamps) emit light. It passes a broader spectrum, so is easier to color correct as well. Since the IDAS will fit into the lens filter holder (in some fashion, I'm going to try EWP's trick) it can be used on any camera I attach to the lens, so I may just sell both my Astronomik filters.

Thanks for that. What a pity - I'd been really excited when they released that filter, and was definitely going to get it. Maybe not now :/

 

[jrista]

I'm glad I'm not the only one who's looked at this. I've not tried the Astronomik full frame in-body filters yet though, and until I get a tracking mount that will take the big lens, it's not a priority. Let us know if it's possible to modify the drop in filters!

Will do.


Regarding the Astronomik filters. My problem is specifically with the CLS-XL clip-in for the Canon FF DSLRs. I have two Astronomik CLS filters, as I also have the one for APS-C. I think the design of the APS-C one, the "CLS" is far better. It only fits in one way (the CLS-XL can be reversed, which can cause problems with vignetting as the vignette the filter frame causes is not uniform....I marked one of the tabs on the sides of mine with a silver dot so I knew which direction to put it in), it fits inside the camera without messing with the mirror, and it does not allow any light leak around the edges.


The CLS-XL has problems with non-uniform vignette, it has a large frame that wraps around to hold onto the filter, which effectively reduces the non-vignetted viewport to the sensor, it does NOT fit in the camera without locking up the mirror, it does not fill the entire space when the mirror is lifted up, and it moves around as the mirror moves up and down in the 1-2mm gap above the filter.


Basically, the CLS-XL is just a disastrous design, it was poorly thought out and hacked together. I don't really recommend it for anyone. Hence the reason I am looking into an IDAS screw-in. The IDAS filters are multi-bandpass, blocking only the key bands where primary LP sources (sodium and mercury vapor lamps) emit light. It passes a broader spectrum, so is easier to color correct as well. Since the IDAS will fit into the lens filter holder (in some fashion, I'm going to try EWP's trick) it can be used on any camera I attach to the lens, so I may just sell both my Astronomik filters.

Thanks for that. What a pity - I'd been really excited when they released that filter, and was definitely going to get it. Maybe not now :/

If you have an APS-C camera, I think the standard clip-in CLS is fine. Well designed. It is only the FF one, the CLS-XL, that has the problems (so, if your using a 6D, which is probably Canon's best astrophotography camera right now, then I would look elsewhere...screw-on filters for standard camera filter threads are probably best, unless the lens simply cannot take a screw-on.)

 

[Loswr]

@ jrista – If there are brick&mortar stores around you which have used items for sale, might be worth dropping in with a ruler to see if they have any 52mm UV filters <5mm thick with evident retaining rings to take out the glass. It looks like Hutech sells unmounted LPS filters as distinct catalog items, but maybe not in 52mm. However, maybe they'd sell the bare glass as a special order if you asked. Might also be worth suggesting they make a 52mm screw-in with a thinner mount for Canon supertele users.

http://www.sciencecenter.net/hutech/contact.htm

 

[jrista]

@ jrista – If there are brick&mortar stores around you which have used items for sale, might be worth dropping in with a ruler to see if they have any 52mm UV filters <5mm thick with evident retaining rings to take out the glass. It looks like Hutech sells unmounted LPS filters as distinct catalog items, but maybe not in 52mm. However, maybe they'd sell the bare glass as a special order if you asked. Might also be worth suggesting they make a 52mm screw-in with a thinner mount for Canon supertele users.

http://www.sciencecenter.net/hutech/contact.htm

I plan to ask them. I've called on a couple occasions, and just been on hold. I don't think they are a very large organization. As far as unmounted filters go, they do have 50mm ones. A 2" filter is, in exact terms, 50.8mm in diameter...so, those ones might work. I really need to get a hold of someone on the phone though, to actually figure out what will work. Even if it does, I am thinking I will still get a mounted 52mm filter, so I can simply screw it onto the front of other lenses, like my 100mm and 50mm lenses. (Although, now that I think about it....I think those might actually be 58mm filter threads...)

 

[East Wind Photography]

@ jrista – If there are brick&mortar stores around you which have used items for sale, might be worth dropping in with a ruler to see if they have any 52mm UV filters <5mm thick with evident retaining rings to take out the glass. It looks like Hutech sells unmounted LPS filters as distinct catalog items, but maybe not in 52mm. However, maybe they'd sell the bare glass as a special order if you asked. Might also be worth suggesting they make a 52mm screw-in with a thinner mount for Canon supertele users.

http://www.sciencecenter.net/hutech/contact.htm

I plan to ask them. I've called on a couple occasions, and just been on hold. I don't think they are a very large organization. As far as unmounted filters go, they do have 50mm ones. A 2" filter is, in exact terms, 50.8mm in diameter...so, those ones might work. I really need to get a hold of someone on the phone though, to actually figure out what will work. Even if it does, I am thinking I will still get a mounted 52mm filter, so I can simply screw it onto the front of other lenses, like my 100mm and 50mm lenses. (Although, now that I think about it....I think those might actually be 58mm filter threads...)

For a 5mm filter you also have to be mindful of the glass thickness which may hinder a remount if it's too thick.

 

[East Wind Photography]

Here is the canon gelatin 52 (mark 1 version). There is simply a door that opens and the filter drops in. Definately only room for the 48mm. The 52 glass won't fit.

I also checked the 52WII gelatin filter on my 300 mkii and it's the same. Glass is about 45mm in diameter and it pops right out once you open the trap door.

 

[East Wind Photography]

So Jon, here is a good question. Once I removed the AP filter from its ring I lost track of which side would face the camera. Coated side or glass side? I don't see any reflectivity difference but who knows. Over 300 subs it might make a difference.

 

[jrista]

So Jon, here is a good question. Once I removed the AP filter from its ring I lost track of which side would face the camera. Coated side or glass side? I don't see any reflectivity difference but who knows. Over 300 subs it might make a difference.

That's a good question. The coated side should be the filter side. I honestly do not know if the LP filters are reversible or not. I don't think an NB filter is reversible, those are pretty specialized...but an LP filter may be different. I do know that when I hold my Astronomik filters in front of my computer screen, it does not seem to matter which direction I hold them, they seem to filter the light from the screen the same way.


Anyway, I'll pay attention when I do this. Very curious about the gelatin filter holder...that 48mm filters fit. I guess I can pull mine out and actually measure it. I have a nice pair of digital calipers that should make short work of it all. I am curious how thick your filter is. I was looking at the IDAS ones, they say 3mm, which seems pretty thick (especially if the most the 52mm screw-in drop-in can handle is 5.5mm in total).