realVivek wrote:
I am not fond of vague quotes, conjectures and making a conclusion out of thin air.
I've not made a conclusion from thin air, it's carefully reasoned from well established principals. I can't conceive of mechanism that would let you gain two stops sensitivity from removing the CFA even if the microlenses were still intact.
realVivek wrote:
A comparison of my monochrome converted RX1 (with a filter that is equivalent to the ICF on the stock camera) on the lens and a stock RX1 cleared any doubts I had.
If you have access to both a converted and stock RX1 you should be able to measure the sensitivity difference very accurately.
Steve, there are reasons but beyond the levels of a photo forum (not a judgment on any of the posters!).
I will add these hints:
1. The sensitivity of a bare silicon sensor (most sensitivity in the green area).
2. How much a micro lens adds to the sensitivity.
It is naive to think of any filter as simply cutting light. Dyes/pigments do more than that.
AZSteve wrote:
On the unrelated question of removing the CFA lowering IR sensitivity, I trust Vivek's observations, but the only explanations I can imagine are both poor: removal of microlenses or, maybe a little more likely, some artifact of the different way monochrome and CFA-retained images are processed.
“Carefully reasoned” from “well established principals”
“If you have access to..”
Matt Grum wrote:
I've not made a conclusion from thin air, it's carefully reasoned from well established principals. I can't conceive of mechanism that would let you gain two stops sensitivity from removing the CFA even if the microlenses were still intact.
If you have access to both a converted and stock RX1 you should be able to measure the sensitivity difference very accurately.
I am not interested in having any more discussion with you.
realVivek wrote:
there are reasons but beyond the levels of a photo forum
Nothing should be "beyond the levels of a photo forum", there are some extremely knowledgable people on here. If you have some insights, please share them.
realVivek wrote:
It is naive to think of any filter as simply cutting light. Dyes/pigments do more than that.
That's literally what a filter does, it filters out light (or more accurately certain wavelengths of light). There are some strange quantum effects with polarisers as I mentioned earlier, but I don't think that applies to CFAs (unless you have evidence otherwise).
realVivek wrote:
I have no idea about these kind of arguments...
“Carefully reasoned” from “well established principals”
CFAs filter out less than 2/3 of light. Even if you somehow kept the microlenses that's less than 2 stops to be gained from removing the CFAs. The reasoning is straightforward.
realVivek wrote:
I am not interested in having any more discussion with you.
That is your perogative but I think you are being overly defensive here. This is a forum for discussion, not for stating absolutes with no option for reply.
DaveFP wrote:
30 seconds would be fine but 1 second a bit short. I will discuss with Kolari.
In my email exchange with Korali today, they indicated that for A7RII and A7RIII, even at ISO 100-200, 20 seconds, there may be light leak. They have A6000 on their website on sale right now, so I just bought one from them with 850 nm. Now I need to find out which of my lenses do not have the hot spot issue.
Douglas Liu wrote:
In my email exchange with Korali today, they indicated that for A7RII and A7RIII, even at ISO 100-200, 20 seconds, there may be light leak. They have A6000 on their website on sale right now, so I just bought one from them with 850 nm. Now I need to find out which of my lenses do not have the hot spot issue.
Congrats!
The A6000 is basically an oversized lens (rear) cap!
Check the primes I suggested (28/35/55). Of course, with a dedicated camera, you can mount any lens and find out the suitability for yourself easily.
On the IR leak, do note what AZ Steve posted about a monochrome converted A7rII (with no special modification to shutter from where the IR leak emanates).
Douglas Liu wrote:
In my email exchange with Korali today, they indicated that for A7RII and A7RIII, even at ISO 100-200, 20 seconds, there may be light leak. They have A6000 on their website on sale right now, so I just bought one from them with 850 nm. Now I need to find out which of my lenses do not have the hot spot issue.
I researched online today and concluded the Sonys are a no go.
p.4 #10 · Is Infrared Photography a Fad (for you)?
I had a full spectrum Nex 5 that I upgraded last year to a full spectrum a7r. I use it only with a Kolari IR Chrome filter (before that just the yellow filter thing and some photoshop actions) for the Aerochrome look. Not really interested in infrared but might look into it someday if filters are affordable. Just tough finding a good compact lens that works well with the Kolari IR filter. Currently using a Contax 35-70mm which is nice, but hefty
p.4 #11 · Is Infrared Photography a Fad (for you)?
realVivek wrote:
Congrats!
The A6000 is basically an oversized lens (rear) cap!
Check the primes I suggested (28/35/55). Of course, with a dedicated camera, you can mount any lens and find out the suitability for yourself easily.
On the IR leak, do note what AZ Steve posted about a monochrome converted A7rII (with no special modification to shutter from where the IR leak emanates).
Thank you! I was dead set to get a FF Sony converted, ARII, or A7RIII, too bad they have the IR LED issues. I figured getting an A6000 is a cheaper way to get my feet wet.
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beavens wrote:
I'm glad you were able to find something to play with - have fun Douglas!!
Please share your results.
Jeff
Thank you Jeff! I guess there isn't much to shoot in dead winter, if my main interest is "snowy" trees.
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DaveFP wrote:
I researched online today and concluded the Sonys are a no go.
Kolari has a lens list.
Yes, I saw their list. The lenses I intend to use for IF are not in their good or poor category. I guess I will have to try them to find out.
Here is my list:
Sigma 14-24 DG DN Art for Sony
Sony 16-35 GM
Voigtland 21 f1.4 Nokton for Sony
Sigma 24-70 f2.8 DG Dn Art for Sony
Voigtlande 35mm F1.2 SE for Sony
Douglas Liu wrote:
Thank you! I was dead set to get a FF Sony converted, ARII, or A7RIII, too bad they have the IR LED issues. I figured getting an A6000 is a cheaper way to get my feet wet.
----------------------------
Yes, I saw their list. The lenses I intend to use for IF are not in their good or poor category. I guess I will have to try them to find out.
Here is my list:
Sigma 14-24 DG DN Art for Sony
Sony 16-35 GM
Voigtland 21 f1.4 Nokton for Sony
Sigma 24-70 f2.8 DG Dn Art for Sony
Voigtlande 35mm F1.2 SE for Sony
p.4 #13 · Is Infrared Photography a Fad (for you)?
Douglas Liu wrote:
I saw some pretty interesting infrared photos so I thought I would give it a try to have some fun. I just bought a used A7RII (will have it on Monday) for the sole purpose of converting it to a infrared camera by Life Pixel, before I found this on their website:
"Note: The Sony A7S II, A7R II, A7R III and A9 use an IR LED as part of their electronic shutter monitor. Once these models are converted to IR, the internal IR LED will contaminate all images shot at exposures greater than 1 second."
Looks like the A7RII is not a good candidate if shooting longer than 1 second could be problematic. I may get a cheaper body for conversion to try out. What I am afraid of is that I will try a couple dozens shots and will never touch it again. I know everyone has different interest, just wondering those who have converted infrared cameras, was it a fad for you or you use it a fair amount?...Show more →
Very interesting to know that MLC successor versions of the original A7 series have this IR LED internally. I am still using my A7R for regular photography, but will keep this in mind if I ever intend to have it converted for IR. The first generation seems to be the better choice here for this reason. I have taken in the past multiple long exposure shots with 10-stop ND filter in IR with my converted 5D MkII. So suffering from this IR LED light in newer Sony A7 models would be certainly be a debit for me.
I am shooting IR since 2007 when this was quite new for digital and not too many people knew about it. I bought a refurbished Canon 5D MkII in 2012 just for the purpose to have it converted for IR (715 nm cutoff) after shooting for years with external IR filter on top of the lens with my old digital Rebel XT. Still have and use this converted 5D MkII camera. I find IR works very well in some situations especially with clouds and foliage. I most often shoot IR in spring and summer. It doesn't replace color photography for me, so I use my IR camera much less and only in situations where it complements my other photography. This said, I really like IR especially for B&W compositions and never found it boring so far. I also still shoot IR film with my Leica M6 camera sometimes with great results - film IR is not the same as digital IR, there is a difference. But you can make a digital IR look-alike film IR in PP.
When I am asked for advice in my IR classes which I instruct, it is often about the cutoff filter recommendation. It is a very personal choice, and there are many more filter options out there in addition to full spectrum (no filter) than 10 years ago. I know some IR shooters who like the false color look, but most seem to prefer the B&W converted IR photo look (me included). Latest and a bit overhyped digital IR filter is the so-called chrome filter from KolariVision which leads to red looking foliage resembling an older Kodak IR film. To use this kind of external filter, the camera has to be converted to full spectrum first.
p.4 #14 · Is Infrared Photography a Fad (for you)?
For clarification: there is no issue with the A7III. Also, there is no indication that the cameras are affected in the silent mode (where available). It is the electro mechanical shutter which has this built in diagnostic IR led that lights up the sensor during low shutter speeds in some models.
Are there solutions? Yes. It is, in principle, possible to replace the offending IR LED with a LW IR LED (there is an example of that on the net) or insulate the shutter unit to minimize (not entirely eliminate) the LED light.
retrofocus wrote:
Very interesting to know that MLC successor versions of the original A7 series have this IR LED internally.
This diagnostic internal IR LED business has unfortunately crept into lens (!) designs as well. Some of the Canon R lenses and Nikon Z lenses have them inside!!
p.4 #15 · Is Infrared Photography a Fad (for you)?
Douglas Liu wrote:
Thank you! I was dead set to get a FF Sony converted, ARII, or A7RIII, too bad they have the IR LED issues. I figured getting an A6000 is a cheaper way to get my feet wet.
---------------------------------------------
Thank you Jeff! I guess there isn't much to shoot in dead winter, if my main interest is "snowy" trees.
---------------------------------------------
Yes, I saw their list. The lenses I intend to use for IF are not in their good or poor category. I guess I will have to try them to find out.
Here is my list:
Sigma 14-24 DG DN Art for Sony
Sony 16-35 GM
Voigtland 21 f1.4 Nokton for Sony
Sigma 24-70 f2.8 DG Dn Art for Sony
Voigtlande 35mm F1.2 SE for Sony...Show more →
If you don’t mind manual lenses and adapters, hunt around for a pentax k28 3.5, should be less than a hundred dollars plus adapter and it’s a gem in infrared
p.4 #17 · Is Infrared Photography a Fad (for you)?
retrofocus wrote:
Very interesting to know that MLC successor versions of the original A7 series have this IR LED internally. I am still using my A7R for regular photography, but will keep this in mind if I ever intend to have it converted for IR. The first generation seems to be the better choice here for this reason. I have taken in the past multiple long exposure shots with 10-stop ND filter in IR with my converted 5D MkII. So suffering from this IR LED light in newer Sony A7 models would be certainly be a debit for me.
I am shooting IR since 2007 when this was quite new for digital and not too many people knew about it. I bought a refurbished Canon 5D MkII in 2012 just for the purpose to have it converted for IR (715 nm cutoff) after shooting for years with external IR filter on top of the lens with my old digital Rebel XT. Still have and use this converted 5D MkII camera. I find IR works very well in some situations especially with clouds and foliage. I most often shoot IR in spring and summer. It doesn't replace color photography for me, so I use my IR camera much less and only in situations where it complements my other photography. This said, I really like IR especially for B&W compositions and never found it boring so far. I also still shoot IR film with my Leica M6 camera sometimes with great results - film IR is not the same as digital IR, there is a difference. But you can make a digital IR look-alike film IR in PP.
When I am asked for advice in my IR classes which I instruct, it is often about the cutoff filter recommendation. It is a very personal choice, and there are many more filter options out there in addition to full spectrum (no filter) than 10 years ago. I know some IR shooters who like the false color look, but most seem to prefer the B&W converted IR photo look (me included). Latest and a bit overhyped digital IR filter is the so-called chrome filter from KolariVision which leads to red looking foliage resembling an older Kodak IR film. To use this kind of external filter, the camera has to be converted to full spectrum first.
p.4 #18 · Is Infrared Photography a Fad (for you)?
johnahill wrote:
If you don’t mind manual lenses and adapters, hunt around for a pentax k28 3.5, should be less than a hundred dollars plus adapter and it’s a gem in infrared
Thanks John! I have seen several lists on the internet regarding the good or poor lenses for IR. The Pentax you mentioned is certainly one of the options. If my existing lenses don't work out, I may try a different UWA or WA lens first.
p.4 #19 · Is Infrared Photography a Fad (for you)?
I have been shooting digital IR since the Canon 20D, initially with a lens-mounted 720nm filter and REALLY long exposures. I then subsequently converted a 20D to 720nm, then a Sony a6000 to 590nm, when I switched to Sony. I now have an a7iii converted to full spectrum and use 590, 650, 720nm, and IR-Chrome most often. I mostly shoot color but also enjoy BW IR. Unlike normal visual spectrum, high noon is not a bad time at all to shoot IR, so it can give you more shooting time.
p.4 #20 · Is Infrared Photography a Fad (for you)?
Grenache wrote:
I have been shooting digital IR since the Canon 20D, initially with a lens-mounted 720nm filter and REALLY long exposures. I then subsequently converted a 20D to 720nm, then a Sony a6000 to 590nm, when I switched to Sony. I now have an a7iii converted to full spectrum and use 590, 650, 720nm, and IR-Chrome most often. I mostly shoot color but also enjoy BW IR. Unlike normal visual spectrum, high noon is not a bad time at all to shoot IR, so it can give you more shooting time.
Thanks for the info, Jim! I am having the Sony A6000 converted right now, may eventually get a Sony A7C converted and hope the tiny new Sony FE 28-60 is good for IR. Would you care to share your thoughts/experience on the E mount lenses that have less hot spot issues for IR?
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