Shashin
Well-known member
Sounds like an urban legend to me, probably started by a film astrophotographer.However, is it true that hour long exposure hits up the sensor and eventually might damage the digital sensor?
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Sounds like an urban legend to me, probably started by a film astrophotographer.However, is it true that hour long exposure hits up the sensor and eventually might damage the digital sensor?
Could simply be the difference in signal processing. Folks like to talk about chips like film having inherent qualities. And to a point they are right. But there is a lot of other things that happen. So the Pentax could be getting better images than the P45+ simply because of signal processing.Not sure what Pentax is doing to allow longer times/less noise as I have never shot the P645, however I have worked with a few night shooters who have and their results were very impressive. From my understanding, the Pentax and P45+ ue the same Kodak chip.
Paul
This is not correct. The Pentax uses a KAF-40000 sensor. The P45+ uses a KAF-39000 sensor.From my understanding, the Pentax and P45+ use the same Kodak chip.
Who said Pentax is getting better images than a P45+? Or are you talking here specifically about higher ISOs? In which case there is no argument - the P45+ is not (and was never advertised as) a high-ISO back.Could simply be the difference in signal processing. Folks like to talk about chips like film having inherent qualities. And to a point they are right. But there is a lot of other things that happen. So the Pentax could be getting better images than the P45+ simply because of signal processing.
6 out of 11 lenses are covered, it would be more accurate to say that the most common H lenses are covered...Also, lens corrections for most Hasselblad H lenses are included in Capture One
One product is still available new with warranty in different mounts, the other one is discontinuedI've been looking at 39mp backs for the H series and what constantly surprises me is the price of the P45+
Why is it so high relative to an entire H3DII 39 system? Especially as they are the same sensor. Based on used prices the H3DII is 30% less. Has lens corrections and enhancements via Phocus etc?
Doug, before you jump down my throat, perhaps you want to reread my post which was simply a comment on Paul's comment on the sensors. If you read carefully, you would see that I just suggested the Pentax files "could" be better because of signal processing. I did not say it was better. The point of my comment was that there is more to a final image than the sensor.Who said Pentax is getting better images than a P45+? Or are you talking here specifically about higher ISOs? In which case there is no argument - the P45+ is not (and was never advertised as) a high-ISO back.
At low ISOs I've never seen any compelling example of a Pentax file which exceeded a P45+ file. Do you have such an example to share?
My apologies. I simply misread what part of the sentence "could" applied to when you wrote:Doug, before you jump down my throat, perhaps you want to reread my post which was simply a comment on Paul's comment on the sensors. If you read carefully, you would see that I just suggested the Pentax files "could" be better because of signal processing. I did not say it was better. The point of my comment was that there is more to a final image than the sensor.
The move from the P45+ to the 160 for me was at first a tough call. I had spent 6 months getting my P45+ up to spec, (mine had the controller card that would not go to 1 hour, BTW a little known about issue). If you are looking for a use p45+ make sure you test it as I am sure there are more out there like mine. Since all warranties are off of the used backs now, it will be harder to get Phase to correct the problem.
For me, it's just the opposite. I used the P45+ for almost 4 years, used it hard. I quickly learned, expose for the highlights, and make sure you don't blow one as it's gone. Thus even at ISO 50, working with the P45+ was a mulit-shot show, most times 3. File size was not that big a deal so that was the way I went at it. I also noticed a big improvement in the 400 and 800 iso after Phase returned my back (new controller card that allowed me to run the most current firmware). But I still saw and still see when I work old files, what I call muddy blacks, and digital weirdness in the shadows. It's like the back was not able to figure out what to record in these parts of the image. Still when the exposure was good the results were top notch.
After a few demo's with Capture Integration with the P65+, I decided to trade the P45+ and upgrade. I also had read Don Libby's and Jack's posts on the P65+ and these helped a lot. Net, the DR of the P65+/160 is a huge step up from the P45+. It's there in the Dxomark scores, but I didn't really know how big it would be. You have so much more room between the shadows and highlights and now I often find it's just like a D800 file. Shoot for the middle you can recover a good bit of the highlights and the details in the shadows are just amazing. At first I wished I had done the P65+ a year earlier, but since I knew I also wanted a tech camera, I waited for the 160. Previous comments on the 2" LCD screen of the P45+ and P65+ are very true. It's a worthless screen and more times than not, when the screen showed me in focus, I would be out.
At first I missed the 1 hour reach. But in reality, for me, it was not that big a loss. Mainly since I shoot at night with the moon and thus I need to be able to stack, not leave the camera open for 1 hour, but instead take a long series of exposures and then combine them. You just get getter results this way. Here you can't use the P45+ as you end up with the dark frame each time, which ruins the sequence. Also in reality, if you are shooting say a 40min shot, it's pretty much one battery one shot as you still have to have enough battery to take the corresponding Dark frame. If your battery expired then the whole shot is gone.
As stated before the P45+ was a benchmark and a breakthrough. Phase was able to break new ground here. But after working with the newer Dalsa chips I am more than pleased to lose my 1 hour ability. Canon and Nikon fill that void very well.
Now with the reach of the D800, I have taken mine to 45 minutes just to see what I got, the 1 hour time of the P45+ is less important. Plus many are using the P645 Pentax at times of 1 hour or more and getting very good results. Not sure what Pentax is doing to allow longer times/less noise as I have never shot the P645, however I have worked with a few night shooters who have and their results were very impressive. From my understanding, the Pentax and P45+ ue the same Kodak chip.
Paul
Or of course you could purchase from a reputable dealer by which means you could avoid all the potential snags of scratched filters, dead ports, bad focus alignment, banged up chassis, missing accessories, "lemons". They would then also be there for you through all of your questions, issues, concerns. You can even get a warranty if it suits your needs/budget. (obvious self interest disclosed here).Eduardo if you can find the serial number of the back you intend to buy then Phase One will be able to tell you the history and what kind of hardware revisions it's got in it.
Steve, I do know why this is. :toocool:But I have shot P25/45 non plus and P25 non plus is limited for the most part to about 40 seconds, while the P45 can go for at least several minutes. Don't know why this is,
The 8x lower dark current does indeed explain an advantage of the P45+ over (most of) the other Plus backs with Kodak sensors. The other 9-micron backs (P20+, P21+) have similar dark currents to the P25+. But three questions arise:but it might explain the bias for P45+ and long exposure compared to those other models. It does indicate the possibility that the P45+ would provide a cleaner long exposure than the other Plus backs, given that the P45 non plus also did.
As it happens, I own a P30+ and do a lot of night photography. For a few weeks, I also owned a P45+, but ultimately decided it wasn't worth the additional expense relative to my P30+ (which I bought used for an almost too-good-to-be-true price) and when I received an offer I couldn't refuse, I sold it.3) Since the P45+ and P30+ have sensors with the SAME dark current parameters (to within a fixed and pretty negligible 10% difference), why doesn't the P30+ have the same reputation for long exposures as the P45+?