petrochemist

Status: Member
Join Date: 27th February 2010
Last Login: 11th May 2022 - 21:33
Real Name: Mike Kanssen
Website: Visit My Website
Occupation: Analytical Chemist
Interests: photography, astronomy, nature, motorsports...

All Forum Comments
Topic / Forum Comment
Interesting development for Pentax Lenses and Sony bodies
Posted in Pentax Digital SLRs
Could be of interest to those of us with a substantial investment in lenses. Hopefully not required after the K3 iii is launched! https://pentaxrumors.com/2020/10/29/new-monster-adapter-la-ke1-pentax-k-to-sony-e-lens-adapter-with-autofocus-aperture-control-and-exif-transmission/I'm certainly keen to try it, getting my huge range of Pentax lenses autofocusing on an IR converted body will be nice. Somewhat typical that i hear about it just 2 days after recieving a DA-nex adapter that will have no use once this new one is in my hands.
Night out in Exeter
Posted in Local Groups and Meetings
As Lenny says cropping can make a big difference to images. But in the first two examples, I find his crop too tight making the images look cluttered which the original didn't. The second two I find the cropped versions an improvement. He's definitely right about these things being personal opinion too! I must admit I'm always a sucker for well taken blue hour shots. Hard to say why but I think no 2 is my overall favourite.
Artificial lighting (?)
Posted in Your Photos
Nice :)
British GT & Support @ Oulton Park
Posted in Your Photos
Nice set George. I was at Donington, but despite the lack of spectators I wasn't allowed out of the paddock/pits area & wasn't allowed to wander into other parts of the paddock... The view from my pit garage was very limited, and there wasn't even anywhere I could get a coffee! :( Probably would have been a good chance to catch up on some post processing. Maybe next time!
Wanted : Mains Power Unit for Mecablitz 45CT-1 45 CL-145 CL-4
Posted in Flash Photography
I would expect it to be rather hard to track down an original unit, but it should be easy to get a generic power supply of the right output & modify it.
Inexpensive Gimbal
Posted in Leads to Deals
It looks very much like the Beike BK-45 I got a week or so ago (for £27). Though the Beike does have an extra bubble level. Looks good at first glance, but drag on the vertical swing tightens/loosens as it swings. The manual only covers it's use for panoramas (suggesting that's it's main function). My only testing so far has been in the dark on a travel tripod where vibration made it quite useless for my 1000mm lens - which also wouldn't balance right on a 4" aria plate, somewhere I have a longer plate. Hopefully I'll get the chance to try it with some other combinations.
Community Spirit
Posted in General Photographic Chat
According to the Daily Express newspapers (and I suppose by extension magazines and books) are sterile due to the printing ink and paper processing, so cannot transmit viruses. But they would say that wouldn’t they? I like the idea of a book swop box I seem to recall something of a national movement for this, there is one in the local railway station for instance.I would hold very little faith in that. Yes freshly made paper & printing ink is likely to be sterile (paper is typically bleached & printing inks contain loads of nasty chemicals) but I don't see this produces any protection from surface contamination later in it's life. The risk certainly isn't high & and will go away after a few days, so it's not something I'd worry about. Using baskets/trollys at the super market is a much greater risk IMO.
Do I switch to another brand?
Posted in Pentax Digital SLRs
lens alone would not be enough to convince me to switch from Pentax, ( I know because I already switched from Pentax to Sony) . Simply put... Pentax lenses generally are superb and usually value priced in their respective classes. for example... My WR DA 100mm macro.... I have an adapter with aperture control to use this lens on my Sony A7III. Why? Two reasons: a) in different macro lens shootouts the Pentax bested the 90mm Tamron and the Sony 90mm may be the highest rated macro on any system.. BUT it's not a huge jump ahead of the Tamron, meaning it's not edging the Pentax out by much... b) I can live with manual focus for portraits and macro shooting, so whatever.... SONY 90mmm macro $1400.00 CDN, Pentax 100mm macro $649.00 CDN, Tamron 90 mm macro $949.00 CDN as of this writing... Who cares if there's more options, with other brands when there's really only a few sensible choices? having fewer choices isn't reason enough to switch, if the choices you have are generally excellent... Pentax not offering pro video specs in ANY camera body..... THAT WAS REASON TO SWITCH! :evil:Nearly all my Pentax lenses can be used with AF on my A7ii. Including many that are manual lenses. My Takumar 300/4 is one of those too heavy for adapting that way. The Auto 110 lenses don't support AF either but they can be used if you're happy to ignore the poorer coverage they work manually (unlike on a PK body).
Aww the K-5 ii.....
Posted in Pentax Digital SLRs
Wayne, just to let you know your original K-5 ii is still in active use, and is also at the 3,000 mark now :-)My K5ii rarely gets used but it does come out for the local airshow. It typically shoots 3000 images a day during the airshow!
Cornish Night Sky
Posted in Your Photos
Excellent image My own efforts have never come out anywhere near a good :-(
K20D infrared?
Posted in General Digital Photography chat
Whatever the benefits of an IR mirrorless camera, it misses the point somewhat. Now debating which filter to have fitted... Thanks all. K.The point is it might be the cheaper option as well as working much better. Even if you use an adapter to use your existing Pentax glass...
K20D infrared?
Posted in General Digital Photography chat
Like Barrie I went for a mirrorless model when I got a converted body. My initial one was brought pre-converted for less than the cost of a conversion. More recently I've brought a FF body & had that converted by on the isle of wight. I should be able to shoot UV as well as IR with the new one, and can fit a clip in filter to return the camera to normal operation too. I've come across a useful on-line, giving contact details etc for each.
What's your latest acquisition?
Posted in General Photographic Chat
I picked up a Sigma 400mm/5.6 yesterday It's the AF variant listed Seems to be in good condition so a real bargain at £15 :shock: It's considerably lighter than my other AF options in the same focal range, so it might get to come out with me more often.
Devon and Cornwall
Posted in Your Photos
Yes all are impressive! For me 4 & 5 beat 7, but 10 must be the winner are those planes or shooting stars? They all seem to be coming from a fixed point and there's not the clear pulsing often seen with aircraft lights, but the intensities look fairly even. I'm sad to say they all put my shots of Cornwall over the summer to shame.
Infrared Hot Spots
Posted in General Digital Photography chat
Thanks Mike. I've heard similar experiences on other forums. It seems to call into question the usefulness of the tables of good and bad IR lenses.They do need to be taken with more than a pinch of salt. If contemplating a new lens for IR they may have some benefit, but I've never bothered with them. I've got quite enough lenses in all reality!
Infrared Hot Spots
Posted in General Digital Photography chat
I've not noticed any effect from the filter used, but there are certainly a huge number of variables that affect hotspots: I've had a lens cause them every time with one body, yet never at all with another. Another lens only seems to give hotspots when focused close Then we have aperture setting, Direction of lighting... I wouldn't consider it surprising for a 850nm to be worse than a 720nm - it is after all working further from the wavelengths the lens is designed for!
Flektogon m42/35mm-f28
Posted in Leads to Deals
I got mine for £10, with 2 other CZJ lenses & a body.:mrgreen: Checking at the time suggested the flektogon alone was worth much more than these values, (~£220 IIRC) but maybe I just spotted the f/2.4 I'd consider both to be excellent deals.
pentax k lens to nikon
Posted in Lenses for Pentax Cameras
Different flange focal distance than Pentax.... so it won't fit. A glass element could be incorporated, but would ruin the image quality plus Nikons can't extract all the magic image properties the way Pentax can. So buy Pentax every time :lol: --Algi is quite right about PK having a shorter flange distance. However it is still possible to use PK lenses without correcting optics, as long as you don't want to focus on more distant subjects. How far away you can focus is a function of the lenses focal length, with wide angle lens it will almost certainly be just macro distances - many long telephotos (which often have focusing rings the turn beyond the infinity mark & are less effected by extension) may still be fairly usable. If you have to use a Nikon body the Z series can be adapted to quality glass without any issues - I think it's even possible to get a degree of auto focus! (Techart do a nikon Z to Sony E AF adapter & their Techart pro will focus/focus tune any lens that can be adapted to Leica M...) The techart pro moves the entire lens up to 4mm to focus fairly effective on lenses under 50mm, longer lenses can need to be partially focused first in the same way as with the Pentax 1.7 autofocusing teleconverter... :twisted:
Wiltshire Downs IR
Posted in Your Photos
I'd prefer it with a little less cloud (2/3 to 3/4 cloud cover) - but that's the case for so many of my shots too, we have to live with what nature gives us weather-wise. To some extent I agree with Phillip about the LHS, but the dark band of conifers (?) are currently on the third and that would be lost with cropping, weakening the left so I'm not totally convinced.
Don’t hold your breath for a Pentax mirrorless
Posted in General Digital Photography chat
I've tried mirrorless cameras and can't stand those awful electronic viewfinders, as for focusing using a 'touch screen' what a load of faffing about! Probably ok for the 'phone snapper' ( don't get me started on THEM! ) but definitely not for meHow old was the EVF you tried? The early ones were certainly dire The ones with my 5 year old mirrorless models are pretty good, except perhaps for action shots. I gather they've improved a lot since then. Having magnified view & focus peaking available in the viewfinder works really well for manual focusing. I've not bothered getting native lenses for one of my mirrorless systems, and I really like the results I get from those tiny Pentax 110 lenses (even though the 18mm doesn't fully cover APSC). One of my MFT bodies has a touch screen focus - I've hardly ever used it, AF works just like a normal camera but it allows the AF point to be moved simply when I have wanted it for closeups it's been a lot less faffing around than using the buttons to select a different focus point. BTW I am very definitely not a 'phone snapper' rarely even having a phone with me (I probably carry a camera 100 times as long as I do a phone in any given year)... I do prefer my k5ii to my mirrorless options for motorsprts & airshows, but thats at least in part down to having AF at a much longer focal length (750mm EFL vs 400mm EFL). In poor light - night, macro & especially infra red - the EVF is a huge advantage over an OVF, so as response times & resolution have improved the benefits of a DSLR have diminshed. I'd love to have a camera with the features of my old mirrorless bodies, a modern EVF & Pentax ergonomics. Sadly the K-01 had none of these!
E Books?
Posted in General Photographic Chat
Hi John. Yes I know you download them but it's paying for them in $ and the exchange rate???. I'll have a think about it. CHEERS Vic.The exchange rate doesn't vary that much - if you assume 1:1 and it still seems reasonable, the inevitable reduction from the true exchange rate is only a bonus. Via pay-pal IIRC you'll actually see the rate the transaction happens at before confirming the payment.
Backwards Zoom Lenses?
Posted in Lenses for Pentax Cameras
I think most of my zoom lenses are shortest at intermediate focal lengths, usually extending slightly for the shortest FL & more for the longest setting. This is certainly the case for at least half a dozen around the 'normal' focal length. I'm sure it's a consideration that comes quite a long way down the list of priorities in lens design, in fact probably so far down it's not even on the page.
What's your latest acquisition?
Posted in General Photographic Chat
Won on a well known internet auction a Sigma 24-70mm. In the listings the images showed the lens hood attached but when it arrived there was no lens hood. Annoying as I've now messaged the seller 3 times and they haven't responded to them :evil:The goods are therefore not as described & you can get a partial refund. Failure to respond will only reinforce your position there.
What's your latest acquisition?
Posted in General Photographic Chat
I've just unintentionally splashed out on another telescope. I placed a minimal bid as a marker & won the auction for a penny! Admittedly it's not a top quality job, but it should provide a few components to play with. I might even replace the eyepiece holder with a connector for a M42 helicoid :)