Jump to content

Interceptor121

Member
  • Content Count

    3801
  • Joined

  • Last visited

  • Days Won

    153

Everything posted by Interceptor121

  1. Hence I suggested to check performance on land first then underwater. The TC will have issues of its own at times and needs stopping down already on land then of course you need to understand what it does in the dome subject to the residual field of view
  2. It is not just the sharpness is the chromatic aberrations you can see green circle around edges. When you then combine them with blurred corners you can have some really weird effect I wonder if the problem occurs even before you are behind the dome port Sent from my iPhone using Tapatalk
  3. That is true. I started submitting underwater images to judged photography competition. Photos with people do better, also landscape shots do well Pictures with fish portrait score very low and macro near zero So generally wide angle better if there are people in get more attention from non divers
  4. Am commenting on a the images we see here and on dpreview they are soft and have CA this could be to do with the TC not being canon not just the dome Full frame will use the entire optic while MFT is a crop so edge aberrations go away TC doesn’t change the focussing distance of the lens I would start checking the situation on land and then work out underwater The other issue is that you need to stop down the lens even more due to the TC
  5. It is very soft with chromatic aberrations on the edges. I had the same experience with Tokina and 1.4x really pretty bad
  6. Just wanted to relax the tone we have all brought back a piece or two but at the end is the same as grey import It is funny when people condemn grey imports but are happy to bring things back themselves and second hand has no VAT anyway This was the thread on Olympus that meanwhile has disclosed they paid JIP 20 millions euro to advice them on the carveout and on top they will fund the working capital of newco with 200 millions So they were really desperate to drop the imaging business that is no longer consolidated in their financials and referred as ‘discontinued business’ Sent from my iPhone using Tapatalk
  7. Try the 30mm macro lens it should still have sufficient depth of field to cover the frame with powerful lights
  8. Are you sure https://www.iatatravelcentre.com/ph-philippines-customs-currency-airport-tax-regulations-details.htm#:~:text=all passengers (18 years of,b. If you live in the philippines you need to declare everything, there is no country with unlimited duty free imports to my knowledge. it may be small but it exists
  9. Typically you are supposed to declare any purchases over a certain limit Whilst digital cameras are not subject of import duty in UK lenses and other parts are and they are still subject to VAT:GST It is different if you buy second hand goods usually. So the fact nobody asks what you did doesn’t make it necessarily more legal than a grey import and of course you can’t service the goods in your country without a valid proof of purchase so you need to take that into account But is a risk some people are prepared to take Sent from my iPhone using Tapatalk
  10. Mine was a rhetorical question in fact. In UK you get import duty plus VAT calculated on the cost plus shipping plus a fixed handling charge So it is not always a great idea
  11. The issue is not magnification or focus multiplication because whilst the camera will appear to magnify the working distance in water is also increasing so the net effect is zero because you have a longer lens further away resulting in the same shot. The problem are pincushion distortion and the amount of water between you and the subject making it not worth to take anything behind a flat port that is not 35mm equivalent or longer This was well explained in an article from David Knight from the now defunct cameras underwater and similar material can be read on scubageek So your 18mm lens with crop is 27mm and this will give some undesired effect albeit not as bad as if you had a 10mm lens
  12. to be honest am not sure there is a camera that can track video AF on translucent subjects. Sony AF is interesting in many ways but in a busy frame the issues is always the same the camera does not know what or who is the subject no algorhytm can fix that without AI to save the exact shape and recognise later. We have now some success in photos but video is a long way and the type or processing in digital camera is not powerful enough you need smartphones type of chip Manual focus you can do with any camera there is no need to go down the road of Sony
  13. There are more cost effective ways to do some birds shooting in your garden One of the easiest is to adapt a full frame lens you can find quite a few options. For example a Sigma 150-600mm 5-6,3 costs £779 I used it at the beginning of lockdown to entertain myself with birds in the garden In hindsight you don't actually need 600mm as many times even air has an issue of suspended particles for example you can have heat radiating from the ground or fog or mist. So having a telescope lens past 400 (800 equivalent) is not always smart and is better to get closer. I now shoot wildlife on land and the best entertainment for me are deer (we have a park nearby and is fabulous) and going to a large zoo where animals have large enclosures birds are easy as they are in my garden though in the winter they are more rare as with the cold small birds die Shots are my instagram https://www.instagram.com/interceptor121/ no single item cost me more than £1,500 so far
  14. I think this lens was designed as a 'statement' it will not do anything to improve the situation for MFT as a segment I believe
  15. I have used the Olympus 300mm f/4 and the Panasonic 200mm f/2.8 primes I had the Olympus on loan for a week and concluded it is a fine lens but 300mm f/4 as start is too long unless you are shooting small birds all the time. So I now have a Panasonic 200mm f/2.8 it comes with a 1.4 TC that appears to have a very very marginal loss. So I have a 200mm/2.8 lens that is fast and if I need reach a 280mm f/4 that performs as well as the Olympus 300 f/4 I wrote a review on dpreview https://www.dpreview.com/forums/thread/4531092 Clearly if small birds are all you shoot it makes sense to start at 300mm if you get a good price however I would not recommend to take a 2x TC and run the lens at f/8 for 600mm
  16. The issue in my image is number 3 sensor reflections (of AF pixels) this is not the same as banding or striping and occurs in a specific scenario with all cameras. PDAF pixels only aggravate it For what concerns the banding and striping This thread explains the specific of Nikon Z7 https://petapixel.com/2018/10/01/nikon-z7s-banding-makes-it-fall-short-of-d850s-dynamic-range-report/ My understanding is as follows: AF pixels do not produce an image so the image has to be interpolated from near pixels. This is done before the data is de-bayered and saved as RAW. The process of replacing those pixels can create artefacts that in certain conditions lead to striping or banding. If you increase the number of AF pixels and there is more interpolation to be done so smaller sensor like MFT or APSC are more prone to problems. I have recently done a collaboration with Bill Claff the owner of the website Photons for Photos that has the largest collection of sensor data you can find on the internet. I submitted data for both my camera on the research for fixed pattern noise https://en.wikipedia.org/wiki/Fixed-pattern_noise#:~:text=Fixed-pattern noise (FPN),above the general background noise. Fixed patterns means in short the chance you will see banding as it means the sensor is prone to create patterns in absence of light I have submitted data for my two cameras that share the same sensor with the only difference being PDAF. The measurement is conducted at low and high gain that is different for each manufacturer and camera. So to give an example at ISO 200 which is low gain for both cameras the camera with contrast detect scored a value of 6% DSNU which is a measure of non uniformity so low values are good The camera with PDAF scored 22% which is a fairly high value. At high gain the camera with contrast detect scored 10% and the one with PDAF scored 14% which is a lower value of the low gain band. In the specific case the AF pixels are 'hot' compared to the neighbour pixels at low gain when the high gain circuit kicks in the AF pixels remain as they are but the neighbour are also hot so the effect reduces and so does fixed pattern noise. So as a paradox the impact is higher at low ISO and as this specific camera has high gain at 2000 it means really for all normal situations you have higher risk than at high gain. This is also confirmed by my experience I get sometimes pretty decent shots at ISO 4000 while I may have low quality shadows at ISO 400. When you look at Nikon D850 vs Z7 the situation is almost similar at low gain the Z7 has 15% DSNU vs 8% of the D850 when they are both at high gain that kicks in pretty early at 400 the DSNU is the same. So this confirms what you read on petapixel this banding actually happens at low ISO which for most people is completely counterintuitive. Nikon in addition has implemented a specific technique to minimise the striping that can actually create banding itself so if you look at Sony A7R series for example A7R3 you see that fixed pattern noise is lower an incredible 3% DSNU at low gain and dropping to 16% at high gain but here high gain is 640. From what I can see also canon dual pixel is effected as fixed pattern is noticeably worse in the EOS R than it was with traditional DSLR. To what extent this is a problem is always the question and my view at current state of data is as follows: 1. Smaller sensor MFT/APSC with large number of AF pixels have pretty bad performance (Olympus OM-D EM1, Canon 90D, Fujifilm XT-3) in terms of fixed patter noise due to the density of AF pixels compared to the area. However the effect is stable or even reduced at high ISO 2. Larger sensors are also affected (Nikon Z, Canon R) to what extent it depends on the technology and interpolation but the trend is stable or getting worse at high ISO 3. Contrast detect sensors or traditional DLSR without AF pixels are generally better especially when high dynamic range is required at low ISO The issue has not been investigated as a trend at this stage and it needs significant effort and data however I can quite clearly see the trend. When I submitted this problem to Bill Claff he wrote me The PDAF pixels are different and certainly can cause more noise particularly Fixed Pattern Noise (FPN). I think there's a limit to how well any firmware can "fix" the effect. I am not particularly interested in investigating the global effect of this issue however I do see a potential problem with underwater photography and banding as this is a problem that does occur at times in water. I also see an issue with dark shadow banding as that occurs a lot with flash photography. Historically banding has been linked to lack of bit depth however it seems much more interesting to look at fixed pattern noise as you can get banding also at high bit depth. When you don't get banding you get other effects generically described as 'noise in the shadows' but what really means is noise is not fine grain but clusters of patterns that look blotchy I would be interested looking at low ISO shots from any of the candidate cameras to see to what extent this happens. I do not have any of those cameras nor am planning to buy them but that is unrelated to this issue.
  17. Some canon DSLR actually have AF pixels on sensor and the 5DIV is one of those. I think also the C300 and other professional video and the 6DMKII None of those however can track objects moving very fast in the frame. The idea is that you pan the camera and the relative speed is still fairly slow
  18. If I remember correctly in live view the D850 works with contrast detect so it won't focus better than any other mirrorless cameras. Same thing any DSLR. You need a mirrorless with phase detect to retain PDAF and video Perhaps you need to think about different strategies...
  19. Nothing special is f/13 the issue starts appearing from around f/8 wider you only see a bit of lens flare You don't see all the AF pixels reflected in the lens depending on the incident angle where the lens flare came from Look closer at your sunburst f/9 posted on dpreview https://www.dpreview.com/forums/post/64485695?image=5 I can see few artefacts there. If you push that to f/11 and smaller the bubble may indeed appear
  20. Does not produce banding or striping those occur because of near pixel interpolation for on sensor phase detect only so this is not generally related to DSLR perhaps I was not clear. So it is only issue number 3 reflections and not necessarily you see pixel shape. I say generally because some DSLR like canon use PDAF on sensor as well not a separate circuit etc In terms of flare we are talking about internal reflections well explained here but you can also google Nikon D750 flare or reflections. I guess it has to do with bouncing on the mirror. The DSLR part was not part of my investigation but when I said DSLR are immune this guy posted some examples saying there is even worse when it comes to reflections. My approach is as long as I don't see them in the image I don't care but now I have been able to reproduce at least a few consistently during day shooting so it is getting annoying. On the other hand no mirrorless camera is exempt More examples on mirrorless can be found with google PDAF striping or PDAF banding Nikon comes up a lot as they have attempted to correct striping and ended up with problem of banding
  21. Go on my channel but there is no Blackwater Nikon are not popular at all for video especially DSLR Sent from my SM-A505FN using Tapatalk
  22. I have no experience in black water dives but autofocus needs light no matter which system so I supposed once you introduce video lights in the mix it is not black water after all? With video lights in the mix get a GH5 over a Nikon D850 the video quality is substantially better as nikon has limited experience in video as it is not their focus and it shows. If instead you require something to focus in dim light I think your chances are slim may want to look to Sony A7SII but all cameras in low light switch to contrast detect and that is not helping autofocus
  23. The 3 issues reported here striping, banding and sensor flare are unrelated to purple fringing which is what you mention. On that specific note this is not longer a specific Olympus Body/ Panasonic lens issue since the OM-D EM1MKII the Olympus and Panasonic both exhibit some purple fringing in certain conditions with any lens with the Olympus bodies producing a more pronounced effect This includes not just purple fringe that can be attributed to UV filter, but also mild green fringing that currently goes unexplained. Generally speaking Olympus sensor coating makes it more prone to chromatic aberrations but this does not mean that the issue goes away on Olympus lenses and is also not true that Olympus lenses have UV coating to eliminate this issue they produce it anyway in certain conditions. For sure some specific lenses have the issue more than others this may be due to an underlying weakness of the lens that is exacerbated by the camera. Purple and green fringing can be corrected in RAW files so I have not specifically focussed on this issue as it can be resolved with some post processing effort relatively easily
  24. Normally you will see ghosting and lens flare more or less controlled. You also have ghosting which your image is an example of. However if you close the aperture to say f/11 and smaller which you do with a sunburst you see some red dots appearing this issue does not occur at wide apertures. Why does it happen? Is a combination of lens flare AND bouncing on the UV coating of the sensor that is made of highly reflective material. The AF pixels make this more apparent however if you push really hard you may see some artefacts on contrast detection too. I have not yet been able to recreate the issue on my Panasonic cameras but I have seen it demonstrated on Olympus cameras with contrast detection. Note this issue applies also to Fuji, Sony APSC for what I know. I have not seen examples on full frame mirrorless however those have other issues
×
×
  • Create New...