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Forum: Pentax SLR Lens Discussion 3 Days Ago  
Are the Focal brand name lenses any good?
Posted By marcusBMG
Replies: 30
Views: 805
A veteran photographer once commented online "every lens is good at f8". Certainly you can exercise your curiosity and check out these lenses, I can suggest you will be perhaps even mildy impressed "yeah decently sharp stopped down, how about that for 10/20 ... bucks". My prediction after that though is that these lenses just clutter up a cupboard.
It pays to be more discriminating. That tends to mean primes from the MF era. Or search for the zooms of particular historic, quality or character interest.
As well as collecting adaptalls, I have a nice little set of komine/kiron made vivs (100-200mm, 28-90mm, 70-210mm, 24-48mm). This latter set is exacly the sort of thing to go for. These are interesting, historic, have optical quality.
Forum: Lens Clubs 4 Days Ago  
Adaptall Mount Club (Tamron).
Posted By marcusBMG
Replies: 3,941
Views: 663,555
as a general rule some exposure compensation is needed with PKA mounts. One thing I learnt from my tests is that the best aperture to chimp from to set that tends to be one stop down, not wide open. Good ones are pretty consistent through middle f's, but you may have an iffy one like the #3 in the test, which showed increasing overexposure.
Forum: Pentax SLR Lens Discussion 12-08-2019, 06:14 AM  
HD DA 55-300mm F4.5-6.3 WR PLM and Teleconverters
Posted By marcusBMG
Replies: 18
Views: 679
The point of a tc would be to get "more reach" ie fill more of the frame with the subject. IME using tc's with slower lenses more often doesn't pay off even if the tc works well with the lens and iq holds up and you are able to compensate with good technique for the slower shutter speeds and increased effect of shake and vibration. Most often the results are little better, if at all, over increased cropping and/or resizing. The more effective way to get a bigger picture of your subject in the end is a camera with more pixels IMO.
I wil qualify that by saying that this can be a bit subject dependent. cooltouch did a study on mflenses stacking tc's on a quality 300mm f2.8. He noted that although the images looked increasingly terrible, when processed and resized it was clear that the stacking had increased the information in the image, specifically the legibility of writing on a small sign. I can suggest that if your subject has fine detail eg feathers, thats what's lost first and tc's are less beneficial. However if eg ships or aeroplanes are your thing then a tc could be more beneficial.
Forum: Lens Clubs 12-07-2019, 06:59 AM  
The Mirror Lens Club!
Posted By marcusBMG
Replies: 1,114
Views: 396,198
Great moon shot Michael. Your exposure almost exactly corresponds to the lunar-11 rule if you factor in the actual T-stop (transmission) rather than f stop. The lunar 11 rule also only applies exactly to a full moon, partial or occluded/eclipsed moons are not as bright.
Last resort to get your focus at the moment Jack: repeated shoot- review enlarged pic on the lcd - adjust. Laborious, but you can get there in the end. Have you tried spot metering? Also try Av mode and bump the exposure compensation right down, see if that stops the view of the moon in LV washing out.
Forum: Lens Clubs 12-06-2019, 11:10 AM  
The Mirror Lens Club!
Posted By marcusBMG
Replies: 1,114
Views: 396,198
I've never been able to see any difference with the 500mm mirrors with or without the flter.
The 300mm f2.8's are also designed to be used with a filter. The main effect is to shift focus slightly - you may not be able to focus to infinity without the filter.
Forum: Lens Clubs 12-06-2019, 10:56 AM  
The Mirror Lens Club!
Posted By marcusBMG
Replies: 1,114
Views: 396,198
mmm thinking about it I think I did run into this problem too when I had my K5, I tended to use my samsung NX20 for moon shots at that time.
Forum: Lens Clubs 12-06-2019, 09:14 AM  
The Mirror Lens Club!
Posted By marcusBMG
Replies: 1,114
Views: 396,198
Try switching to spot metering, make sure the moon is centre frame. Or manual mode, set the exposure using lunar 11 rule.
Forum: Lens Clubs 12-05-2019, 12:09 PM  
The Mirror Lens Club!
Posted By marcusBMG
Replies: 1,114
Views: 396,198
Magnified live view is the way (depending on camera). IME focusing the tamron 500mm by eye at f8 (~ T10) with standard focus screen is inherently imprecise, even with the tenpa 1.35x OVF magnifier I use, even in best conditions (and forget it if its dull light). By eye use focus bracket techniques, eg shooting a short burst while slightly moving position (deiberate sway), or a quick sequence while touching the focus through the focus confirm signal point.
Forum: Product Suggestions and Feedback 12-05-2019, 09:47 AM  
Mount focusing DSLR for vintage lenses
Posted By marcusBMG
Replies: 11
Views: 595
This had occurred to me also. Basically a built in auto fine-focus mechanism based on a small amount of movement at the mount for primarily MF lenses. Would be something different, an interesting USP.
Forum: Pentax SLR Lens Discussion 12-04-2019, 03:00 PM  
Pentax DFA 150-450mm vs Sigma DG 150-500mm APO HSM. K3-ii test pics.
Posted By marcusBMG
Replies: 21
Views: 823
Not really - I acquired the sigma after i dropped my k3 which affected AF, so not representative. The 150-450mm was good for me with AF, although if the subject was very OoF the camera might hunt ineffectively - qiuicker to manually spin the focus in the right direction until the camera picked up the focus.
Forum: Pentax SLR Lens Discussion 12-04-2019, 11:22 AM  
Pentax DFA 150-450mm vs Sigma DG 150-500mm APO HSM. K3-ii test pics.
Posted By marcusBMG
Replies: 21
Views: 823
There are two more little plus points for the sigma: a better case comes with it (decent thick foam padding), and the sigma has a built in strap attachment point on the tripod mount foot.
Forum: Lens Clubs 12-03-2019, 02:23 PM  
300mm plus Lens Club: discuss your long lenses
Posted By marcusBMG
Replies: 32,387
Views: 3,070,788
You can now peruse my comparison of the sigma 150-500m with the D FA 150-450mm.

Pentax DFA 150-450mm vs Sigma DG 150-500mm APO HSM. K3-ii test pics. - PentaxForums.com
Forum: Pentax SLR Lens Discussion 12-03-2019, 02:20 PM  
Pentax DFA 150-450mm vs Sigma DG 150-500mm APO HSM. K3-ii test pics.
Posted By marcusBMG
Replies: 21
Views: 823
There are already some threads discussing how "bigma's" compare to the DFA 150-450mm:


Pentax 150-450 vs Sigma 150-500 questions - PentaxForums.com
Pentax 150-450 vs Sigma 50-500 OS - PentaxForums.com
DFA 150-450 vs Sigma 150-500 - PentaxForums.com

Since I have the DFA 150-450mm and have just acquired a non-OS example of the Sigma DG 150-500mm APO HSM I have been able to take comparison images at different focal lengths.


150mm, the tower on the Telford railway bridge. I thought both lenses were really good at 150mm, both sharp from wide open. The sigma perhaps showed a little more fringing/purpling on some backlit twigs, and the DFA seemed a bit better at coping with the dynamic range from the shady side to the sunlit side. Both lenses were good across the frame, so I haven't bothered with edge crops.






300mm, one of the turrets on Conwy Castle. Unfortunately I couldn't get the tourist in in both sets, so the DFA shots are just of the same point of the turret. Again I was impressed with both lenses, both lenses looked softer at f11 but that I think was due to some shutter shake creeping in at ~1/200th shutter speeds, or perhaps my not letting the lens settle for long enough after changing the aperture on camera before firing the shutter with the cable release.


800px




450mm (+ sigma @ 500mm), another turret.






Sigma @ 500mm and DFA @ 450mm.

dfa 450mm
sigma 500mm

Distant Focus. The house in the crop on the Great Orme is about 3km away (sorry about the pole, best I could do from the driveway). Atmospherics can be the main limiter of IQ in these cases, but this was a favourable, still, clear frosty morning. Neither lens managed to resolve the car number plates! The sigma pics at 500mm highlight a drop off in iq from 440mm. IQ was again good across the frame with no particularly significant falloff visible with either lens in this case.

















Close focus. The DFA focuses to 2m, the Sigma to 2.3m. Focus distance here was approx 2.5m. It was immediately noticeable that the sigma focus breathes much more than the DFA. I aimed to cover the width of the banknote. The sigma was at 440mm, the DFA at 330mm (though I didn't exactly equalise the field of view, the DFA is a bit wider). My first efforts were sub standard - shutter shake influencing results with both lenses. I didn't use any extra lighting, just the sunlight filtering into the conservatory, so shutter speeds were sub 1/100th. Corrected second go using mirror lock-up and higher (400) ASA. These test pics most clearly distinguished between the lenses, the DFA distinctly better.





Forum: Photographic Equipment for Sale 12-03-2019, 10:17 AM  
For Sale: Pentax-D FA 150-450mm F4.5-5.6 ED DC AW. UK sale.
Posted By marcusBMG
Replies: 3
Views: 488
PentaxForums.com Marketplace Listing

Item for Sale
Pentax-D FA 150-450mm F4.5-5.6 ED DC AW. UK sale.

Asking Price
999.00 GBP

Item Location
nr Conwy N. Wales (UK)

Item Description
Pentax D FA 150-450mm, case, box, caps.

Reluctant sale of my plum lens - D FA 150-450mm f5.6 due to need to finance new camera body to replace a damaged K3-ii. Just looking to get my money back, I got lucky with purchase hence sub 1G price for you.

999. Paypal, cheque (delivery after cheque clears), CoC.

PLUS free bean bag. I normally include one of my diy'ed bean bags with my online telephoto lens sales.
I also have a DA 1.4x teleconverter I can be persuaded to let go too - 199.

EU/Europe: payment in , add 20 as a contribution towards higher paypal fees, msg me re courier options (likely to be of the order 50-60 fully insured).

Post: Royal Mail special delivery 29 fully insured (cheapest fully insured option).

I have been very careful with this so it's still more or less completely minty. Perfect working order. With original box etc. As you can see, one extra point: I have added a stainless steel eyebolt as a strap attachment point this works well but if you don't like it all you have to do is unscrew it, only leaving the tapped hole. You can also have a spare clip on strap I have if you want.
I have posted a number of times in the 300mm lens club thread with this lens eg post 30240.



Click on the pic to see big pic.



Click on the pic to see big pic.



Click on the pic to see big pic.








Are you the original owner of the item being sold?
No

Are you selling or trading this item?
Selling

Item Condition (Key)
Used
Excellent

Shipping Destinations
Europe Only

Shipping Charge
29

Shipping Services
Royal Mail/ Parcel Force

Accepted Payment Types
PayPal Check/Money Order Other (Elaborate)

Return Policy & Additional Details
Refund by agreement or return and full refund if not as per. Post to be paid by returnee.

Please send me a private message if interested in the item!
Forum: Lens Clubs 12-01-2019, 03:21 PM  
300mm plus Lens Club: discuss your long lenses
Posted By marcusBMG
Replies: 32,387
Views: 3,070,788
I made a couple of ~ half price so to speak scores off ebay recently. One disappointed a bit, the other is a deal that might prompt me to let go of my DFA 150-450mm.
The sigma apo 400mm f5.6 in PKA mount - well I have been trying to find a good one for a while. Two previous purchases were rejected and returned because suffering from the bane of these 400 apo's - the cement of an internal group deteriorating to haze and/or speckling. The seller told me his camera shop had inspected and passed this lens as good. On arrival, everything looked good, a boxed minty one, the notorious "zen" body paint only slightly sticky in a couple of spots. But on close inspection: yep,that hazed group! Only a marginal effect on IQ so I just prompted him to give a bit of a refund.
I don't know why the sigma 150-500mm apo hsm didn't bid up but hey I'm not complaining! Partly because it's the non-OS one I think, partly because the description was a bit suggestive of a rather worn one, a little smidgen of fungus, partly ..just because! And I have to say so far I like this lens. I carried it up to Aber Falls today albeit without using it (pics in Sigma thread) and the weight difference over the DFA is really rather significant. IQ wise I have been doing some comparison pics and it is very competitive - thread pending.
I am think about getting my back on the DFA 150-450mm because I had a near catastrophe with the K3-ii. Trying some digiscoping, I turned away from scope + camera, resting on a window sill, for a moment, only to see it all slowly rotate and topple to the hard floor. The camera took the impact on its corner. To my relief, everything still worked but things had shifted very slightly, the lens release barely worked. And then when I tried the DFA and the sigma subsequently, AF is intermittent or non functional. So I am in the market for a replacement and letting go of the plum lens, while painful, would give me the moolah. Maybe I should offer a swap for a K1..??

Some bigma pics off the feeders at the Spinnies, all 450mm or 500mm, f7 (addendum due to server resizing these are not as sharp as they should be - I think the problem is the vertical dimension, horizontal is withinn the 1270px limit):









Hand held, f9, 500mm.


And with the DFA @ 450mm f7 for comparison.






Forum: Pentax SLR Lens Discussion 12-01-2019, 11:08 AM  
Komura 135mm f/2.5
Posted By marcusBMG
Replies: 3
Views: 322
The sort of item you spot and pick up for a few € out of curiosity. Not remotely worth €80 - reseller just trying it on.
135mm is a focal length that i think was easy to make and whose optics were well understood = proliferation of good ones. Check out Carl Zeiss Jena, Jupiter, Tair, Tamron adaptalls .... as alts to pentax oem.
Forum: Lens Clubs 12-01-2019, 10:23 AM  
The Sigma Lens Club- All lenses
Posted By marcusBMG
Replies: 2,421
Views: 375,875
Taking advantage of the current delightful sunny interlude in the autumnal monsoon I headed up to Aber Falls looking for fieldfares. No luck, my 150-500mm was unused.





The N facing falls don't get the sun at this time of year. A goodly amount of water coming down thanks to the monsoon...


Lacking an ND filter 1/6th at f22 was the best I could do.


Being such a popular spot, it's a pedestrian superhighway.



No doubt the superwide II is one of the best legacy 24's.
Forum: Lens Clubs 11-30-2019, 08:22 AM  
Manual Zoom Club
Posted By marcusBMG
Replies: 768
Views: 69,708
Getting some good results there Ed with the adaptall 80-210mm.
Forum: Lens Clubs 11-25-2019, 03:55 PM  
300mm plus Lens Club: discuss your long lenses
Posted By marcusBMG
Replies: 32,387
Views: 3,070,788
OK you might want to PM Adam on this, but I think one reason is if you have a http: link rather than a https: link the server rules mean you see the link not the pic. Also the image size is a factor (max 1270px across IIRC).
Forum: Pentax Forums Giveaways 11-24-2019, 10:45 AM  
Sticky: PentaxForums 100 Year Giveaway - November - General Raffle Entry Thread
Posted By marcusBMG
Replies: 400
Views: 7,801
why not
Forum: Digital Processing, Software, and Printing 11-20-2019, 09:53 AM  
Windows 7 support ends 14 January 2020
Posted By marcusBMG
Replies: 72
Views: 1,951
Download "windows media creation tool". This can perform an in situ win 10 upgrade (like for like ie home edition for home edition) of your win 7 installation automatically using your existing win 7 key. If you have something else like xp then its a bit tedious to first install win 7 off any media and then upgrade but as long as you have a win 7 key (if necessary a COA is easily acquired off eg ebay for v little) you should be fine, on occasion I have had to use the microsoft auto telephone line to get a code.
There's plenty of online info if you google.
Forum: Troubleshooting and Beginner Help 11-17-2019, 01:56 PM  
Tele-Vivitar - 500mm - Focus to Infinity?
Posted By marcusBMG
Replies: 9
Views: 441
If the focus ring is slipping then you may well have lost the infinity focus position. Look at the focus ring: are there three small set (grub) screws to hold it in position? are they loose?
To correct the infinity focus, rotate focus to infinity position ie to its infinity stop. Loosen the set screws and back the focus ring off a little bit, retighten.
Forum: Pentax SLR Lens Discussion 11-17-2019, 01:15 PM  
Options to extend reach
Posted By marcusBMG
Replies: 43
Views: 2,138
Agreed.

???????

A eg 90mm lens on a Q gives you a completely different FoV than on apsc. The 12MPx of the sensor are all in that portion of the image circle, this is not the same as simple cropping or enlargement. It's about results. You (and the OP) can check out the results of using telephoto lenses on Q's in the adapted lenses tested thread. And here's a moon pic - Q + tamron 500mm mirror.
Don't get me wrong I agree with what I think you are saying: there's no cheat, no short cut. But for the OP to get, as I imagine, a eg bird filling rather more than a fraction of the viewfinder, well a Q is one way.
Forum: Pentax SLR Lens Discussion 11-17-2019, 11:26 AM  
Options to extend reach
Posted By marcusBMG
Replies: 43
Views: 2,138
+ 1 for prev answers. Your "reach" options, of which there are more in this digital age, are


  1. more focal length - lens and/or teleconverter.

  2. More pixels.

  3. smaller sensor (= sensor pixels concentrated in a smaller area).

Lens options at budget indicated are stricly limited. Something like the takumar 500mm f4.5 might cross your path. I can recommend the sigma 500mm f7.2 apo, MF PKA mount, ticklish focus, good iq, it's a bit of a sleeper in the s/h market, can definitely be acquired for less than $200 and doesn't usually suffer from the haze of an internal cemented group that almost always afflicts the contemporary sigma 400mm f5.6 apo. Mirrors already mentioned. Most of the vintage 400's I have tried don't really do better than the 55-300mm. A 1.4 x tc is certainly workable with the 55-300mm but do you really gain anything in the actual results?


More pixels is a good option but a more recent pentax dslr is unlkely to be had for $200.

Smaller sensor - a Q is well worth considering, married to a high res lens like a 90mm macro gives you pushing 500mm equivalent. And +1 for a superzoom/bridge camera with eg 600mm/800mm equiv as a realistic and very practical, easy lightweight option. Photographically there are slimitations, they won't normally do RAW and the internal processing can be not what you might want (biased towards contrasty postcard sort of look IME...). And these options give enormous depth of field compared to long lenses on apsc/full frame, big advantage with eg pics of flocks of birds.

And then there's digiscoping. Previously my efforts with a HR66 scope by opticron were disappointing, but I recently got a HR80 - an old model - for around your budget and this is better. TBH to get best results with digiscoping then you really need the best scopes eg Swarowski, Leica, so really much depends on what you want to achieve.

Pics: HR80 + K3, opticron 41111 digi adapter (eyepeice projection), 27x HDF eyepiece. RAW, cropped and pp, 1:1 pixel peep. Worth bearing in mind the effective f stop is something like f32, well past normal diffraction limits.
The digiscoping mode I haven't really looked into (mainly bc am one of the diminishing band of luddites w/o a smart phone) is photographing the exit pupil from the scope with a small sensor camera. I did a bit on my HR66 with a panasonic LX5, (has a good optic) but wasn't impressed.
Forum: Repairs and Warranty Service 11-16-2019, 01:41 PM  
Good JIS screwdriver set for SMC (analogue era) lens repairs?
Posted By marcusBMG
Replies: 24
Views: 688
You're UK:

micro tools europe

Search: JIS
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