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Forum: Pentax SLR Lens Discussion 2 Days Ago  
Best "cheap" lens.
Posted By marcusBMG
Replies: 38
Views: 1,551
A couple more thoughts:


Tamron adaptall SP 90mm macro. Best value and most readily obtainable of this class of lens - image quality always impresses on first acquaintance, a versatile optic that covers the 135mm full frame equivalent standard potrait focal length. Not difficult to acquire for ~$100.

Tamron adaptall SP 60-300mm. Putative #1 for best MF zoom readily available sub-$100 on the market. Excellent IQ through the zoom range, beats many of the macro lenses (inc the adaptall 90mm above) with 1:1.55 close focus.
Classic 70-210mm - kiron "zoomlock". Innumerable options of this type, it was such a standard lens for a long time. Big ones, small ones, fast ones, more brands than you've ever heard of.... very few bad ones, pretty much they'll all perform stopped down a bit (as the aphorism says, few bad lenses at f8). My suggestion: the kiron zoomlock f4. All round IQ and particularly good colour rendition. Both mine cost less than 20ea (one pkm one pka).You can see my test pics here.


Ok that was 3 sorry...
Forum: Pentax SLR Lens Discussion 2 Days Ago  
Best "cheap" lens.
Posted By marcusBMG
Replies: 38
Views: 1,551
No brainer! The 50mm f1.7's are basically the best price/IQ going. Knocks the socks off the kit lens 50mm vs 50mm - and more than 3 (three!) stops faster.
Forum: Pentax SLR Lens Discussion 6 Days Ago  
Non-K, Non-42 Adaptable Lenses
Posted By marcusBMG
Replies: 15
Views: 502
On a pentax? You are just holding the lens against the camera mount (the bayonet being smaller than K-mount bayonet)?
Forum: Pentax SLR Lens Discussion 6 Days Ago  
Non-K, Non-42 Adaptable Lenses
Posted By marcusBMG
Replies: 15
Views: 502
Old olympus OM, original Nikon F* and contax-yashica CY mounts (see here) all have similar or slightly longer registration distances than PK, and the bayonets are very similar in dimensions to PK which is why the "multimount" works. The latter is in fact one of the two best ways of using eg a CY mount zeiss distagon on a pentax. The other is a custom leitax mount swap. I've often thought it would be nice to try a classic "zuiko" or two on my K5, but basically getting it on would require a little judicious grinding/filing of the OM bayonet. But it might be worth it, the zuiko 50mm f1.8 is actually a much classier metal lens than the plasticky smc-a 50mm 1.7. DIY mount swapping is mainly not worth the effort, though there are cases where it might be eg a less common mirror lens - and I have a project on the back burner to look at converting my FD 400mm to PKA...
*Nikon F can often be squeezed on to Pk in any case. It's not very secure and the lens IME is usually upsidedown, but it works. Note that the later AI/AIS mounts have protruding connections that prevent any mounting on a K-mount.

T-mounts are a generic screw-on swappable mount, originally attributed to tamron but used by many manufacturers to this day. The mount does not allow aperture connections so lenses are typically preset, but that makes them cheap (my info page on t-mount isn't up for the mo after my bruv in law switched servers without telling me...).
Forum: Pentax K-01 05-13-2018, 06:16 AM  
stabilized mirrorless bodies for mounting my M42 lenses?
Posted By marcusBMG
Replies: 45
Views: 1,197
A potential value option is a samsung: I paid approx a hundred () for my NX20 20MPx apsc s/h. EVF is good, fully artic lcd, instant magnification of the evf with one button press for very accurate focus with MF. But I am not impressed with the noise as soon as asa is bumped. My impression is: probably not as good as the equivalent sony but at the price I am not complaining.
Cheap simple adapters for M42, Pk etc readily available.
Forum: Pentax SLR Lens Discussion 05-12-2018, 05:59 AM  
Centon mc 500mm
Posted By marcusBMG
Replies: 14
Views: 563
I routinely point people who are interested in a reflex 500mm to the tamrons. It's not difficult to pick up one of those for not much more than you paid, there's lots of them around. Gerneral assessment would be that they are better than the "generics" - I think they deserve a certain cachet as "industry standard" so to speak. However I note that the spec of the centon (ebay ad 253615771677) is rather similar to the tamron: long focus throw, good close focus, so it would be interesting to see how the centon shapes up, however the review here of a quantaray 500mm which looks very alike isn't promising . All the 500mm f8 mirrors have the same issues: difficult focus due to extremely narrow DoF and dim viewfinder (actual light tranmission more like T10), minimising shake/vibration at 750mm equiv on apsc dslr. I actually rarely use my K5 on these, the evf's on my mirrorless camreas do better, and I never leave home without my bean bag!
FYI:

500mm Mirror Lenses

Pro Optics 500mm f6.3 Mirror lens - A hands-on review - Bob Atkins Photography

One thing I can add: my tamron makes an excellent almost pocket sized 25x spotting scope with the 02F eyepiece adapter.
Forum: Pentax Camera and Field Accessories 05-09-2018, 12:03 PM  
Tamron F-AF 1.4TC vs. Pentax TC
Posted By marcusBMG
Replies: 20
Views: 640
Check out this thread:

Teleconverter challenge Sigma vs Kenko vs Tamron X1.4 - PentaxForums.com

I don't have a comparison with the pentax tc, but the kenko/sigmas/tamron 014f (adaptall) for me are in the same ball park IQ wise.
Forum: Pentax SLR Lens Discussion 04-30-2018, 06:22 AM  
m42 zoom lens thoughts
Posted By marcusBMG
Replies: 9
Views: 471
+1, the full range can be used with an easily obtainable and cheap M42 mount. The earlier "adaptall-1" lenses have an A-M switch like many M42 fixed mount lenses, which lends to easy stop-down aperture priority operation.

Tamron Adaptall Lenses - Pentax Lens Review Database

Otherwise many M42 mount zooms date from the early days of zoom design and are typically (but not always) way short of later and current IQ. Classic lenses like vivitar series one are readily found in M42 mount - they're good.
Forum: Troubleshooting and Beginner Help 04-28-2018, 06:29 AM  
What does this mean - 35mm equivalent?
Posted By marcusBMG
Replies: 12
Views: 826
Because the 35mm film format was so dominant everybody became familar with how images looked using this film size ie what the field of view would be. Most digital cameras are made with sensors that are smaller than that film size however. The smaller the sensor the narrower the field of view is with a lens of a particular focal length. This doesn't matter: WYSIWYG! What you see is what you get! However many photographers are so used to 35mm that they find it helpful to still have that as a benchmark comparison, so we have this "crop factor" which gives us the 35mm field of view. So by way of example, 50mm is the standard lens on 35mm, giving a field of view similar to that by eye alone. With a pentax dslr, all except for K1 have an "apsc" sensor, the field of view with 50mm is less. It is the same as that given by focal length x the crop factor 1.5x = 75mm on 35mm film/full frame sensor.
Manufacturers also find it useful to inform the consumer what the range of focal lengths on a particular camera means using this yardstick.
Forum: Lens Clubs 04-26-2018, 09:08 AM  
The Tammy Club!
Posted By marcusBMG
Replies: 2,696
Views: 441,455
Another trick I use is focus bracketing - fire off a wee burst while simultaneously moving the focus a mm or so through optimum position. That's also a trick often cited in U-tube videos on hand holding - middle pics in the burst tend to be the best re shake.
Forum: Lens Clubs 04-26-2018, 06:25 AM  
The Tammy Club!
Posted By marcusBMG
Replies: 2,696
Views: 441,455
Good effort Mike, hope to see more pics with your adaptalls either here or in the adaptall thread. I tend to agree with Skodadriver that the 500mm can do better. Your 16MPx image when resized should sharpen up nicely, your squirrel is a bit soft (but still a nice capture). As a rule of thumb, the trad 1/focal length to get a shutter speed fast enough to counter shake needs to be amended to allow for the sensor size ie 1/750 (1.5 x 500) or faster. My experience on my K5 is that the balance between noise and shake is to err for more noise ie up the ASA to eg 1600 which would bounce your shutter speed to 1/500. But even then I would still try to use a tripod/bean bag on a post/monopod/anything to help stabilise - at 750mm equivalent it is difficult to hand hold and get good results at anything other than ideal conditions ie bright sunshine giving 1/x000 shutter speed.
The other difficulty is focus. I have these days settled on a 1.36x VF magnifier with the stock screen, the magnifier does help significantly but I still find visual focus with a lens like the tammy 500mm rather hit and miss - f8 is just too slow, too dull in the VF, and although I get a good focus cue from the camera it's just not quite accurate enough. I would suggest a loupe on the lcd, and magnified live view. In practice I normally use my mirrorless camera instead - instant 5x/7x magnification in the EVF.
Forum: Troubleshooting and Beginner Help 04-26-2018, 06:05 AM  
Haze in middle element, how significant is it?
Posted By marcusBMG
Replies: 15
Views: 545
Well it varies, but generally speaking haze is worse news than fungus. Like the previous responses I have lenses eg tokina ATX 35-200mm with light haze on a rear element and it has a large effect on IQ - foggy pics. You could ask the seller to provide sample pics.
If the image of the lens interior is an accurate depiction of the extent of the haze ie peripheral then the sellers claim of no effect on IQ - specifically on apsc cameras - may well be true. But I agree price is OTT.
Forum: Lens Clubs 04-25-2018, 01:23 PM  
The Tammy Club!
Posted By marcusBMG
Replies: 2,696
Views: 441,455
And another tulip with the f5.9 200mm ' f8, extension tube.
Forum: Lens Clubs 04-25-2018, 06:21 AM  
The 300mm plus lens Club discuss your long lenses.
Posted By marcusBMG
Replies: 28,476
Views: 2,493,704
Your Oly 10 (exif says GX8?) looks a LOT less noisy than my old G1 WPRESTO - did you need to do much noise reduction?
Forum: Lens Clubs 04-22-2018, 01:30 PM  
The 300mm plus lens Club discuss your long lenses.
Posted By marcusBMG
Replies: 28,476
Views: 2,493,704
I decided to lighten the load and switched to my tamron 55BB 500mm mirror. I usually use my NX20 with this lens because of the advantage 5x/7x focus mag gives in the evf. Particularly when cropping a lot there is zero focus latitude, millimetric adjustment required. At least the tamron has a big focus throw - much superior to the off-brand ones, vintage and current, in that respect.

Meadow pipit.


Little ringed plover, this was the best of a bunch of shots. Only slightly smaller than the ringed plover, quickest point of ID is the black bill as opposed to yellow with black tip.
Forum: Lens Clubs 04-19-2018, 02:11 PM  
The 300mm plus lens Club discuss your long lenses.
Posted By marcusBMG
Replies: 28,476
Views: 2,493,704
Took advantage of the mini-heatwave to muscle my bike up the Sychnant (puff puff...).
Missed the flycatcher but caught the willow warbler. K5, 60B + 014F (=420mm).





Forum: Lens Clubs 04-17-2018, 11:51 AM  
The 300mm plus lens Club discuss your long lenses.
Posted By marcusBMG
Replies: 28,476
Views: 2,493,704
I was taking some test pics with a newly acquired tc - a sigma 1.4x, non-apo - and there were two cormorants on the musselmans raft. So I used them as a subject, and then, just out of interest I tried stacking the sigma with an adaptall 014F tc on my 300mm f2.8 60B.
Samsung NX20, sigma 1.4x top 2 - 1/200sec; 014F + sigma bottom 2 - 1/160sec. Same PP. 1st pics show whole frame.







Mmm .. not much difference in the end result. But, I think, a viable 588mm f5.6'ish combo. One more:


The "apo" tc might be better...
Forum: Pentax SLR Lens Discussion 04-16-2018, 03:52 PM  
Teleconverter challenge Sigma vs Kenko vs Tamron X1.4
Posted By marcusBMG
Replies: 54
Views: 6,674
Correct
(still updating...)

Actually I need to redo the apo test pics with the NX20. Crop doesn't really illustrate my conclusion...
Forum: Pentax SLR Lens Discussion 04-16-2018, 03:37 PM  
Teleconverter challenge Sigma vs Kenko vs Tamron X1.4
Posted By marcusBMG
Replies: 54
Views: 6,674
I now have a copy of the sigma 1.4x tc that Mark was testing at the start of this thread. So here's some comparitive test crops.
Samsung NX20, tamron adaptall SP 300mm f2.8 60B, same test subjest - the musselmans raft.




[/img]





Looking at these crops and comparing to those of the "apo" version (see post #40) , though the comparison is compromised a bit by using a different camera, that the "apo" is better is clear, specifically in terms of contrast and fringing at the wide apertures. As the lens is stopped down IQ improves and pretty much becomes the same.

Just for interest I stacked the sigma 1.4x tc with the adaptall 014F tc, making a 588mm f5.6'ish combo. Thse came out better than I thought they would actually.




Forum: Pentax SLR Lens Discussion 04-15-2018, 03:29 PM  
Sigma 100-500mm - anyone know anything about it?
Posted By marcusBMG
Replies: 6
Views: 499
The sigma history page lists a 100-500mm apo - 1985, but no further info.

SIGMA History – 1961 to 2010 | Sigma Lounge
Forum: Lens Clubs 04-15-2018, 02:14 PM  
The Tammy Club!
Posted By marcusBMG
Replies: 2,696
Views: 441,455
I had a little hit with an old tamron 200mm see post 2644.
Now I have acquired that lens non-identical twin - the 200mm f5.9. Since it's also tulip bloom time of year, I was able to see how that lens does.
Very similarly as you can see. Some test pics suggest that the f5.9 is a tad softer than the f6.3.
Forum: Repairs and Warranty Service 04-15-2018, 11:51 AM  
What to Glue the Distance Window of Tamron Adaptall-2 Lenses
Posted By marcusBMG
Replies: 3
Views: 207
I've been using this stuff to weld polycarbonate (perpsex type stuff) sheet and other things, like a router bit box made of clear plastic simliar in kind to what you want to glue:

Model X Pro 50ml PLASTIC WELD Cement Glue Styrene ABS Perspex Acrylic | eBay

It works great! Whether it will work on the plastic used for the tamron lens window will depend on what type of plastic it is precisely, but in general terms acrylic like plastic is exactly what this is for.
Forum: Lens Clubs 04-12-2018, 11:04 AM  
The 300mm plus lens Club discuss your long lenses.
Posted By marcusBMG
Replies: 28,476
Views: 2,493,704
The great crested grebes didn't breed last year, but they're looking busy now..





These last two with my tamron 300mm f2.8 60B + newly acquired sigma 1.4 x tc, non "apo" this time, Samsung NX20. Some comparison pics indicate it is pretty much as sharp as the apo one but not as well corrected - more fringing and haloes etc creeping in specifically at open apertures.

This was a quick stacked tc's experiment - the sigma + adaptall 014F (=588mm focal length), f5.6 on the lens, 400ASA:
Forum: Lens Clubs 04-11-2018, 08:05 AM  
The 300mm plus lens Club discuss your long lenses.
Posted By marcusBMG
Replies: 28,476
Views: 2,493,704
Just PM Adam, Pete, he'll be happy to park a pdf in an approriate place. Update actually he prefers to respond to a thread here:

https://www.pentaxforums.com/forums/3-site-suggestions-help/
Forum: Pentax SLR Lens Discussion 04-09-2018, 06:21 AM  
Lightweight/compact telephoto legacy lenses (m42 or K)
Posted By marcusBMG
Replies: 30
Views: 1,060
I consistently advocate the tamron adaptall 90mm f2.5 SP macro #52B/BB as one of the best price/perfomance options available.

Go up to 135mm - much better focal option on 35mm film than aspsc digital - and there are a huge range of good lenses around including Jupiter/Tair/Carl Zeiss Jena/Tamron adaptall/Vivitar close focus/Pentax's/Taks/... Both the CZJ and the Jupiter 37A are compact and quality, tho not particularly fast at f3.5, and being M42 or t-mount-type wont have auto aperture..

Smallest zooms: tamron adaptall 58A 70-210mm, tokina SD 70-210mm, both not bad... but not great either.
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