NEX 5 + IR 760nm Filter

Started Aug 3, 2010 | Discussions
Adam Cheung Junior Member • Posts: 43
NEX 5 + IR 760nm Filter

I bought a cheap Massa IR filter for fun few days ago. I use it with a step up ring (49mm to 67mm). I tried the filter these two days and the result is not entirely satisfactiory. Partially, coz I am new to IR photography so I have many things ignored probably. No lens hood is used since I was a step up adaptor. What I found in my photo is hotspot, and vignetting and strong flare. Perhaps it's the cheap fliter, or perhaps it's about me with no skill at all.

Most of the photo are taken with high ISO with long exposure. So, the noise is visible even not viewing in 100%. I assume that NEX 5 is very not sensitive to IR? Any comment?

P.s. using long exposure, I really realise how power hungry my NEX 5 is. I am gonna buy a spare battery.

rrcphoto Veteran Member • Posts: 6,173
Re: NEX 5 + IR 760nm Filter

the flare is normal, hotspots are most likely the lens - however, the smaller registration distance may also play a factor in that if you are using a kit lens.

IR's mostly better by removing the cut filter from in front of the sensor, which leads to better results - especially on a EVIL system.

most modern day sensors have pretty strong IR cutoffs - and don't respond well to filters.

Goldenlens Forum Member • Posts: 64
Re: NEX 5 + IR 760nm Filter

These picture look great. They are really somethin special. Well done.

Royal1 Senior Member • Posts: 1,406
Re: NEX 5 + IR 760nm Filter

No, I think the results are spectacular. Nice job and the camera surprises me that it can do that well and not leave a spot in the center from the low pass filter. I have to give it a try. Thanks for sharing.

Tom

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rrcphoto Veteran Member • Posts: 6,173
Re: NEX 5 + IR 760nm Filter

well to be honest, that's horrible bleeding or color casting .. either from the filter itself (could be) .. or the fact that the registration distance is so tight, and IR wavelengths will act differently than normal visible light wavelengths.

Unless you added the false color back in there around the edges.

I'd be curious if you can do some more tests .. keep the sun at your back and see if you get the color casting - you shouldn't .. also lens hood is probably a necessity or at least shade the lens with your hand while shooting.

I've been debating on one or more NEX cameras assuming they update the UI for infrared work, as it should be cheaper to flip these to true IR camera bodies than others.

to the poster above - the camera has nothing to do with hotspots - the lens is the culprit of that.

Gregory Kemp Contributing Member • Posts: 668
Re: NEX 5 + IR 760nm Filter

What is it in the UI specifically that you would like to see that would make it more useful for IR? They will never do anything on purpose that helps infrared, at least not at this point in time, camera companies dont care at all about IR photography. I love IR photography and think its sad that there is not more interest. I think a lot more users would give it a try if features similar to nightshot were offered that can flip the hot mirror out of the way but still allowing normal IR photography rather than the amplified nightshot mode. Or they could even offer a dedicated IR cam. I am thinking about sending my NEX-5 to Precision to have a 715nm conversion performed on it, at this time they are unsure if it is possible because the new Cybershots with Exmor sensors have the IR block filter fused to the sensor, so I really have my fingers crossed that Sony didn't make the same mistake with the NEX.

Greg
--
http://www.flickr.com/photos/gkemp/

OP Adam Cheung Junior Member • Posts: 43
Re: NEX 5 + IR 760nm Filter

Sure, I will try to have more tests with what you've suggested. But it's raining here, will need to wait for few more days.

Right, after reading some links on the web, it seems that the hotspot is related to lens. Btw, both 16mm and 18-55mm kit lens seems both suffer slightly from it (I will need to check this again though)

About the color cast, I hope it's not sth about the flange distance. But turning the photo into B&W/ or desaturate the corner of the photo can still make the photo looks better.

technic Veteran Member • Posts: 8,932
Re: NEX 5 + IR 760nm Filter

rrcphoto wrote:

well to be honest, that's horrible bleeding or color casting .. either from the filter itself (could be) .. or the fact that the registration distance is so tight, and IR wavelengths will act differently than normal visible light wavelengths.

It's a bit similar to the result from the old Canon 18-55 (non-IS) zoom on Canon DSLRs with IR filters in the 600-750 nm range. Probably caused by insufficient correction in the lens for different wavelengths. I think it has more to do with the specific lens design than with the short register distance.

I've been debating on one or more NEX cameras assuming they update the UI for infrared work, as it should be cheaper to flip these to true IR camera bodies than others.

some people say that in the NEX the IR blocking filter is fused to the sensor, so removing it would be VERY difficult. Quite a change from previous models like 7x7, 828, H9 that will give better IR results out of the box (in Nightshot mode).

to the poster above - the camera has nothing to do with hotspots - the lens is the culprit of that.

agree. The result is not really bad for a standard, unconverted, camera. But it seems the 16mm is not very good for IR. Bummer, because this would be my wavelength of choice for IR. The hotspot does not seem much worse though than on the 717, and for that camera it can be easily removed in PP. The color bleeding is a more serious problem.

But hey, if someones figures out how to remove the IR blocker you can always mount a Zeiss ZF-IR lens like the 18 or 21mm Distagon

rrcphoto Veteran Member • Posts: 6,173
Re: NEX 5 + IR 760nm Filter

technic wrote:

rrcphoto wrote:

I've been debating on one or more NEX cameras assuming they update the UI for infrared work, as it should be cheaper to flip these to true IR camera bodies than others.

some people say that in the NEX the IR blocking filter is fused to the sensor, so removing it would be VERY difficult. Quite a change from previous models like 7x7, 828, H9 that will give better IR results out of the box (in Nightshot mode).

ugh, I hope not .. that would turn an alright and interesting camera into a meh one for me at least.

it would also be a deviation on other sony sensors to date as well, because the d300, etc are IR filter removable .. unless nikon did it differently than sony .. to be honest though, I haven't seen any resources advertising removal of sony IR filters - I presume that's simply because there's not alot of people using sony gear versus the other two major brands.

Gregory Kemp Contributing Member • Posts: 668
Re: NEX 5 + IR 760nm Filter

It was me who brought up that the NEX sensors might have the IR block filter fused, this is something I got from Mark Soares of Precision Camera when I inquired with him about having my NEX-5 converted. He said that in the new ExmorHD Cybershot models, the block filter is fused to the sensor making them impossible to convert, they have not yet tried to convert an NEX. I am probably going to be the guinea pig for that unless someone else sends their NEX in first.

With lenses, the best thing to do is try a ton of them and find the ones that give the best IR results. I have a small arsenal of Minolta MF lenses that I want to try on a converted NEX for example. To my knowledge, Zeiss only offers 3 ZF-IR lenses:

-Distagon T* 25/2.8
-Planar T* 50/1.4
-Planar T* 85/1.4

See their Lenses for Industry page for more info - http://www.zeiss.com/lenses4industry

If my NEX is able to be converted, there is a good chance I will buy all three of those lenses eventually, but I would go for the 50/1.4 first.

Greg
--
http://www.flickr.com/photos/gkemp/

technic Veteran Member • Posts: 8,932
Re: NEX 5 + IR 760nm Filter

Gregory Kemp wrote:

I am probably going to be the guinea pig for that unless someone else sends their NEX in first.

OK, I'm holding my breath

I'm interested in the NEX for IR photography, but I'm not a fan of the NEX interface. So I will only buy if IR turns out to be a valid option, until then I will use my modified dsc-f717.

With lenses, the best thing to do is try a ton of them and find the ones that give the best IR results. I have a small arsenal of Minolta MF lenses that I want to try on a converted NEX for example. To my knowledge, Zeiss only offers 3 ZF-IR lenses:

another webpage on the Zeiss site says that 7 lenses are available in ZF-IR version, including the 18 and 21mm Distagon. But it says something like 'on request', so maybe some of them are only available as special order. I definitely want a wideangle as my 'standard' IR lens, so only the 18 and maybe 21mm would do.

I think that in general older lens designs are better than new ones (because of the coatings, mostly) but yes - it is best to try out as much lenses as possible. And who knows, maybe I can use my Canon 15-85 on the NEX, some people say is performs pretty OK in infrared.

rrcphoto Veteran Member • Posts: 6,173
Re: NEX 5 + IR 760nm Filter

the 15-85 waves hand side to side I evaluated that one but saw a glimmering of wavelenght smearing .. but i could have just been my sample.

want to go on the cheap .. OM zuiko primes.

also a nicer size when compared to the NEX.

not to mention you could probably get nearly a complete prime set for one ZF-IR prime

the 35mm shift also works with IR .. it's pretty sweet.

IF you can find it .. it's hard but you see them on Nikon mounts - tokina 17mm 3.5 RMC's ..

works great on IR.

usually less than 100 bucks used.

rrcphoto Veteran Member • Posts: 6,173
Re: NEX 5 + IR 760nm Filter

Gregory Kemp wrote:

It was me who brought up that the NEX sensors might have the IR block filter fused, this is something I got from Mark Soares of Precision Camera when I inquired with him about having my NEX-5 converted. He said that in the new ExmorHD Cybershot models, the block filter is fused to the sensor making them impossible to convert, they have not yet tried to convert an NEX. I am probably going to be the guinea pig for that unless someone else sends their NEX in first.

i'll keep on bumping this thread and nagging you even though i'll probably wait until the next firmware update or next NEX model to fully commit to two new IR bodies .. especially non DSLR ones.

technic Veteran Member • Posts: 8,932
Re: NEX 5 + IR 760nm Filter

rrcphoto wrote:

the 15-85 waves hand side to side I evaluated that one but saw a glimmering of wavelenght smearing .. but i could have just been my sample.

I can't really test it because my 450D is useless for IR (too long exposure etc.).

want to go on the cheap .. OM zuiko primes.

also a nicer size when compared to the NEX.

yes, good suggestion - are you sure they work well for IR? The Zuiko 3.5/21mm might be a good choice but is not really wide on NEX, and a used 18mm Zuiko is very expensive AFAIK.

Too bad I sold my Zuiko primes about five years ago, never thought I could use them again on a DSLR

rrcphoto Veteran Member • Posts: 6,173
Re: NEX 5 + IR 760nm Filter

28mm is a nice walk around on a cropped.

21/3.5 up i've tested and used with IR converted bodies.

just have to watch for flare - which is par for the course...

and the tokina 17mm is the wider one you are looking far - although not as compact as the olympus lenses.

technic Veteran Member • Posts: 8,932
Re:Ir lenses

rrcphoto wrote:

and the tokina 17mm is the wider one you are looking far - although not as compact as the olympus lenses.

I used the tokina 17mm long ago on my OM-2, and the quality was far behind my 24/28mm Zuiko lenses. Sharpness was OK, but pictures had a bit dull look, not the snappy pictures with great color and contrast of the Zuiko lenses. Maybe for IR the difference is smaller, but I'm a bit prejudiced against this tokina lens. I have never used the Zuiko 3.5/21mm, but I guess it is has the same high quality as the 3.5/28mm. And I love a lens that is as compact (and solid) as possible.

GaryW Veteran Member • Posts: 9,481
Re: NEX 5 + IR 760nm Filter

Those look pretty neat. I would try it with raw mode though. I think false colors are to be expected. I dunno about the hotspot.
--
Gary W.

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rrcphoto Veteran Member • Posts: 6,173
Re: NEX 5 + IR 760nm Filter

GaryW wrote:

Those look pretty neat. I would try it with raw mode though. I think false colors are to be expected. I dunno about the hotspot.
--
Gary W.

no they are not to be expected at all. not like that.

rrcphoto Veteran Member • Posts: 6,173
Re:Ir lenses

technic wrote:

rrcphoto wrote:

and the tokina 17mm is the wider one you are looking far - although not as compact as the olympus lenses.

I used the tokina 17mm long ago on my OM-2, and the quality was far behind my 24/28mm Zuiko lenses. Sharpness was OK, but pictures had a bit dull look, not the snappy pictures with great color and contrast of the Zuiko lenses. Maybe for IR the difference is smaller, but I'm a bit prejudiced against this tokina lens. I have never used the Zuiko 3.5/21mm, but I guess it is has the same high quality as the 3.5/28mm. And I love a lens that is as compact (and solid) as possible.

21/3.5 is a gem .. and the tokina is a gem especially on IR .. besides, where else can you get a $100 UWA? that works on IR

on a FF 5D it was fine .. not spectacular though .. but on a cropped body .. it's more than up to the task.

PeteGanzel
PeteGanzel Senior Member • Posts: 1,417
Re: NEX 5 + IR 760nm Filter

rrcphoto:

I'll be cracking open a NEX-5 within this week and I'll keep you posted.

Pete
--
http://www.pbase.com/pganzel

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