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Forum: Pentax SLR Lens Discussion 02-11-2017, 06:38 AM  
500/4.5 SMC Takumar infinity focus issues?
Posted By Ben_Edict
Replies: 19
Views: 3,339
I had the same perceived focus issues years ago, when I got my copy oth the 500/4.5. I readjusted the focus, but it is a tedious task. After that, the images were not sharper at all.
I made comparisson shots with other 500mm lenses (Meyer Optics 500/5.6, Tokina 500/8 mirror) and in real world shooting, they all delivered comparable results. The sharpness of shots over long distances is compromised by atmospheric limitations (what astronomers call "seeing"). THat is part of the problem, which cannot be resolved. At short distances, this effect is neglible.
Also, we shouldn't forget, that the lens design is very old and resolution and constrast modulation may simply not up to the task to be really useful for modern high-res DSLRs.
And lastley, there is the problem, to avoid camera shake or motion blur, which such a long and heavy lens. You will need a VERY sturdy tripod and head combo, to steady this lens - and still very short exposure time are preferable.

By the way: with very short exposure time you can also improve the sharpness of moon shoits, as you may "freeze" a moment of good seeing and reduce blur, this way.
Ben

P.S.: I know, this thread is old, but the issue pops up now and again...
Forum: Pentax SLR Lens Discussion 02-06-2017, 08:08 AM  
Mamiya M645 to K mount adapters?
Posted By Ben_Edict
Replies: 6
Views: 3,097
The weight of the 645 lenses isn't exceptional and many Pentax lenses are in the same weight-league. So, obviously the usual provisions apply. Don't cary the camera on its neck-strap, with a 500/5.6 Mamiya lens attached... But don't do that either with the Pentax 500/4.5 or a 300/2.8 or a Bigma etc. It's I think, more a question of torque (excerted by longer lenses), than one of absolute weight and some common sense should be applied.

By the way: the soft focus lenses would be about the only reasons to attach medium format lenses to a PK body, as most other focal lengthes are covered by generic Pentax or third party glass.

Ben
Forum: Pentax SLR Lens Discussion 02-20-2016, 03:12 AM  
Remove front Objective?
Posted By Ben_Edict
Replies: 17
Views: 1,517
HI BUtch

I don't think, seeing the lens' layout, that a rocket blower would provide enough air pressure, to dislodge a particle on the inside of the front element. The elements are usually contained within a secondary, tight barrell, which you will only see, when you remove the moving parts (aka focus and zoom rings) of the lens. I haven't disassembled my own 10-17 though. Unless, the dust specks really are visible in the images, I wouldn't care.

Ben
Forum: Pentax SLR Lens Discussion 02-16-2016, 05:00 PM  
Remove front Objective?
Posted By Ben_Edict
Replies: 17
Views: 1,517
The problem with acetone is, that it will sip into the lens and might also dissolve the lens cement in the first cemebted group (directly behind the fron element). But ofcourse you are right, that using heat is a dangerous path. I more or less mentioned it, to dissuade the TO from that operation, because removing dust specks is hardly worth the risc.

Ben
Forum: Pentax SLR Lens Discussion 02-16-2016, 04:57 PM  
Pentax 100mm F4 Macro - K,M,A Difference?
Posted By Ben_Edict
Replies: 22
Views: 1,209
You should also see it from the consumer's point: The K lenses were designed in an era, when black and white film was still pretty standard. You needed filters to make the best of that film and standardizing on a common filter thread for a whole lens series reduced the numbers of filters needed and the necessary expense. All camera makers took that approach, though many settled on 55mm threads. When Pentax introduced the M-series the standard filter thread was reduced to 49mm, which was the result of the race for more compact cameras (Olympus being the other leading contender). But Pentax made (in my view at least) the mistake to value compact over fast lenses. That was alright for consumers, but Pentax lost out in the pro market with these slow lenses and the M-series cameras. And I think, they never recovered from that loss.

Ben
Forum: Pentax SLR Lens Discussion 02-15-2016, 02:41 PM  
Remove front Objective?
Posted By Ben_Edict
Replies: 17
Views: 1,517
Hi Butch

Pentax probably glued the retainer ring into place, as they've done with other lenses too. In the past I repaired several lenses, even complicated ones (like the 28mm shift) and had to heat the retainers to soften the glue. I wouldn't do it with the fish-eye, though. I would guess, you need to work your way from behind, removing the zoom and focus rings in order to get to the real lens barrel. From there you might be able to unscrew the whole front assembly, which should enable you, to unmount the front lens. I don't believe (but cannot prove it), that the front element cannot be loosened, by just removing the retainer ring. The only hints I have found so far is the schematics on BDimitrovs site. Though usually I won't hesitate to disassemble lenses, when necessary, I would not come near the front lens with a spanner tool. I would in all probability scratch the element, when the spanner slips, which ought to happen...

Ben
Forum: Troubleshooting and Beginner Help 11-22-2015, 12:42 PM  
Used DA* 60-250mm, strange "dust"?
Posted By Ben_Edict
Replies: 12
Views: 976
From the image I would guess, yes some dust and "flakes", but no fungus or the like. But the halfmoon part at the top, shouldn't be there. I don't have that particular lens, but it isn't a cheapo one, so the zoom ring should turn smoothly all along. If there is a certain point with higher resistance, that is not correct.

Ben
Forum: Troubleshooting and Beginner Help 11-21-2015, 07:00 AM  
Used DA* 60-250mm, strange "dust"?
Posted By Ben_Edict
Replies: 12
Views: 976
Hi Shinra, it would be helpful if you could post some images of the specks. Also, What do you mean by focusing element? Usually I wouldn't expect that "flakes" of any kind appear out of nowhere inside the lens when the focusing clutch is moved, so that's certainly not normal.

Ben
Forum: Pentax SLR Lens Discussion 09-19-2015, 03:31 AM  
Need lens advice.
Posted By Ben_Edict
Replies: 13
Views: 986
If your 15mm already did not provide enough angle of view or just barely enough, I cannot see, that it would make sense to add a 16-60 or 17-50 of whatever brand.

I know that problem quite well and use the Sigma 10-20mm zoom, when I really need the wide vier or don't have room to step back. Sometimes I also use the Pentax 10-17 fish-eye, but it wouldn't be my first choice as a stanrad wide-angle for indoors shooting.

Yes, zooms lack contrast and can exhibit slightly blurry corners. But if stopped down beyond f/8, I find the images very acceptable. And if you shoot for printing standard sized photographs to give away, that is a no brainer anyway. Also, some post-processing with Lighroom or similar, using the appropriate lens profiles, cleans up the images nicely. Especially for indoor shooting, you would be hard pressed not to pp your images.

So, I would really recommend, on of the real wide angle zoom to complement your existing kit. I find it even more important, than buying into the really fast primes, though I have lots of them and find them indisoensable for my kind of shooting.

Regards
Ben
Forum: Lens Clubs 06-17-2015, 02:39 PM  
The Mirror Lens Club!
Posted By Ben_Edict
Replies: 921
Views: 333,866
A plano-parallel "lens", such as the rear filter will shift the focus slightly backwards. The difference between the focal plane with and without filter in place is small. That is easily compensated with longer lenses by re-adjusting the focus and will get unnoticed. There are a few lenses, where the filter serves other purposes as well, mainly reducing colour aberrations, but that is more often the case with front filters. Lenses that require a front lens (quite common with older 300mm f/2.8 lenses), will indeed be sharper when the filter is in place, than without it. There was a very nicely illustrated and well-informed thread in an Olympus discussion forum about that, where the images published clearly showed the improved sharpness with the filter in place.

Ben
Forum: Pentax Camera and Field Accessories 02-06-2015, 12:18 PM  
Zoom bags - any danger for the lens?
Posted By Ben_Edict
Replies: 8
Views: 905
This thought never even occured to me. Basically the same weight will rest on the lens when transported in a bag with the camera attached - and that is, what I have been doing for the last 30+ years. I usually have the lenses "face down" and never ever have noticed any detrimental effect. The added weight of the camera is not really much and the lens is quite strong along its axis, because the tube will take the force. Just make sure, that there is nothing hard protruding directly onto the front element.

Ben
Forum: Pentax Camera and Field Accessories 01-29-2015, 07:45 AM  
Does anyone have a Billingham Hadley Small bag for a compact K-5 II kit?
Posted By Ben_Edict
Replies: 7
Views: 1,639
We use two of the older original Headleys (among some other BIllinghams and many other LowePros ect.). The Billingham Headly will swallow a K5 and one sizeable flash gun (a Metz 54 for instance) and one larger lens on the camera + 1 more large or 2 more small lenses. But you will need to provide your own separator if you stack lenses. I always use pieces of outdoor foam sleeping matresses for that prupose. I am not quite sure, whether the Headly Small is the same size or a bit smaller than the old Headly, though. Anyway Billingham bags are nicely made and nearly indestructible, which justifies their pricing in my eyes.

Ben
Forum: Pentax Camera and Field Accessories 01-29-2015, 07:39 AM  
Linhof tripods
Posted By Ben_Edict
Replies: 6
Views: 1,337
I have had several Linhofs over time and still use one for video. They might have plastic parts, but I have never seen a broken one. Old Linhofs tend to be cheap and much better, than anything new costing two or three times as much.

Ben
Forum: Pentax SLR Lens Discussion 09-20-2014, 04:21 AM  
Pentax FA 50mm f/1.4 should I?
Posted By Ben_Edict
Replies: 54
Views: 4,591
Go for KEH - and I would opt for the cheaper FA 50 including the caps. I have bought several lenses from then and their rating is very conservative. An EX lens will be just that: excellent.

The 43mm is a very different lens and worth the money, because it a gem.

Ben
Forum: Pentax SLR Lens Discussion 09-19-2014, 12:51 PM  
Pentax FA 50mm f/1.4 should I?
Posted By Ben_Edict
Replies: 54
Views: 4,591
I have been using the M 50/1.4, the A 50/1.4 and A 50/1.2 and the FA 50/1.4 and the FA 43/1.9, indeed I have the all sitting in my cupboard and some slower 50s on top. The M50 is the least desirable of the bunch. The FA keeps the lens formula of the A-series with added AF. So whether you buy an A or the FA is more a personal decision, than a question of image quality. I like the FA very much, because it's compact and lightweight. The 1.2 is much heavier and so I leave it behind much more often, than the FA.

And size and weight is a more decisive factor, than I thought in the past. I would never buy the DA 55 for its sheer bulk alone. The FA is somewhat soft wide open, as was any other lens with such a fast max. aperture at that time (with a few noteable and very expensive exceptions). The Nikons did not do better in any respect. And then there is a lot of misconceptcion around about the perceived lack of contrast wide open. Most of the exapmle images I have seen, where people complained about lack of contrast, were simply not in focus or the user did not realize how shallow the DOF is at 1.4. And as you can see with many other fast lenses, contrast will degrade massively, outside the focus plane.

So I would not hesitate to recommend the FA 50/1.4, if you need a fast and still affordable lens. For your birds it is probably more useful than the 43mm, because of the longer focal length and because its nearly an f-stop faster. Your image quality limiting factor will in all probability not be the lack of contrast, buth the shaloow DOF, when used wide open. And you will soon realize, that you need to stop down to f/4 to get good photographs of your bird, in which case the FA performs perfectly.

Ben
Forum: Pentax SLR Lens Discussion 07-14-2014, 01:12 PM  
Pentax-A* 645 300mm F4, a good choice for budget telephoto?
Posted By Ben_Edict
Replies: 15
Views: 1,425
I had the old K SMC 300/4 in the past. It is big, heavy and shows very strong CA and purple fringing. I sold it off and got an A* 300/4, which is a wholly different beast. Sleak, relatively lightweight (considering its all metall construction and old fashioned optics) and focuses nicely, if one doesn't need AF. Fringing and CAs are not an issue and a slight remnant fringing can be easily removed, without destroying sharpness. Overall it is a very sharp lens and well-worth the extra money over the old K version.

Besides that, the old K desperately needs a tripod ring, which isn't available (except for a plastic thingy by a hobbyist, which flexes too much), whereas the A*, due to its much reduced weight and bulk excerts much reduced torque on the camera mount and can be used on a tripod, without fear of tearing out the mount off the camera body.

Ben
Forum: Pentax SLR Lens Discussion 07-11-2014, 12:53 PM  
Iceland Trip
Posted By Ben_Edict
Replies: 16
Views: 2,205
I think your zoom choices are sound, but I would take the 43mm with me at all cost. You will need both: its faster max. aperture and its sharpness. With the 16-50 you have to step down to f/8 to get really sharp images. So the 43mm will give not only much shorter expsoure times, but also offers a way to apply DOF selectively.

I have been travelling through Iceland for several weeks and when I was away from any storage facility, walking through the rough backcountry I had to minimize my equipment, down to only a Leica M body with the 35/1.4, 50/1.0 and 75/1.4. I was very happy with the results and did not miss longer or shorter fls, as I tried to concentrate to make the most out of the three primes. I valued their speed beyond anything, because light is not really bright in the mornings and evenings, when the mood is especially photogenic.

Ben
Forum: Pentax SLR Lens Discussion 02-21-2014, 01:57 PM  
Trying to figure out white haze in photos
Posted By Ben_Edict
Replies: 15
Views: 1,371
No a UV cut filter won't help here, as there is not much UV lighting in your indoor shot at all. What you see is the typical result of using a very fast lens fully open in a low contrast scene. The Tokina is certainly a good lens, which is pretty sharp, as far as I know, but with the aperture fully open, it will show lousy contrast. Looks nearly as bad as my old 135/1.8 Soligor, when used fully open. Nice for portraits, but for anything else, you need to step down the aperture to f/4 or f/5.6, to getter much improved contrast.

Ben
Forum: Pentax Camera and Field Accessories 06-25-2013, 02:07 PM  
Bag for K-r
Posted By Ben_Edict
Replies: 13
Views: 891
The smallest Billingham Hadley will do fine and leave some space for accessories, without being bulky. We have two those bags and they are really among my favourites.

Ben
Forum: Pentax Camera and Field Accessories 06-25-2013, 02:05 PM  
In search for a heavy tripod
Posted By Ben_Edict
Replies: 38
Views: 2,566
Good choice, I think. I was heavily contemplating one myself for my camcorder - but finally went with a Linhof twin-shanks tripod. But I am still tempted by a Berlebach or Wolf, as I have wooden tripods for my telescopes and they perform admirable.

Ben
Forum: Troubleshooting and Beginner Help 06-15-2013, 10:26 AM  
Handheld macro, suggestions/advice needed for image sharpness
Posted By Ben_Edict
Replies: 31
Views: 2,605
Flash mainly works so well, because the flash duration is extremely short and thus freezes the movement. a continous light would have to be extraordnarily bright to give you the 1/10,000s exposure time a flash will easily provide...

Ben
Forum: Troubleshooting and Beginner Help 06-15-2013, 10:11 AM  
PEF files to JPEG
Posted By Ben_Edict
Replies: 20
Views: 5,536
How big are the files in question? Are they exactly the same size as PEF-images which you know are working?

Ben
Forum: Troubleshooting and Beginner Help 06-15-2013, 10:09 AM  
PEF files to JPEG
Posted By Ben_Edict
Replies: 20
Views: 5,536
The Thread Opener uses Mac OSX and can open PEFs with the Mac OSX onboard tools. The files in question are damaged, that seems to be the real problem, as he can open some of those files, but not all.

Ben
Forum: Troubleshooting and Beginner Help 06-15-2013, 10:07 AM  
PEF files to JPEG
Posted By Ben_Edict
Replies: 20
Views: 5,536
The Thread Opener uses Mac OSX

Ben
Forum: Pentax Camera and Field Accessories 06-15-2013, 01:12 AM  
In search for a heavy tripod
Posted By Ben_Edict
Replies: 38
Views: 2,566
The 1/2s is just a medium length of time. The time for vibration dying out is different for any combination of tripod legs, head and camera kit on top. It can be anything... And in all honesty, the 2s delay of the Pentax DSLRs is too short, when using long lenses. I always preferred the old method of simply fixing the mirror in its upward position (MLU), as the LX or several Nikons offered. That is the best solution, in my eyes at least.

By the way, I am not argueing against you or anything you wrote, I am just emphasizing, that the approach Pentax nowadays offers is short of what would be very useful for long exposures.

Another point is wind. Even if wind is nothing nowhere near a storm, which would topple over a tripod (I have had that, even with a heavy tripod), it will introduce vibration. This induced vibration can of course not be eleminated bei shutter delay or the "hat trick". It can only be minimized by a very solid tripod/head-combination and a nicely balanced camera on top (to counter excessive torque).

Ben
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