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Forum: Lens Clubs
1 Day Ago
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In macro mode at 200mm. Slightly cropped square, resized. 1:1 pixel peep crop below. I doubt my macro lenses would do much better.
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Forum: Pentax SLR Lens Discussion
12-03-2019, 02:20 PM
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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.
UPDATE: another point of comparison, the sigma apo 100-300mm f4 at 150mm. Very similar iq.
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.
Bird Focus. I did look at the possibility of acquiring a taxidermy specimen for authenticity but good ones are a fair wack, so I picked the kingfisher ornament up for 99p and the owl for a bit more. This portmanteau was set up at a distance of just over 5m, this was just right for frame coverage with both lenses (the kingfisher ornament is 16.2cm high). Note that the sigma at 500mm has no advantage over the D FA at 450mm due to focus breathing. If you think you might go with the sigma because you get a bit more at 500mm, well at this range, you don't!
Light was so so, clag over the hills blocking the low sun, but I was ok with that as an opportunity to look for fringing. I had to do a fair bit of spot removal on these pics, and tweaking of exposure + a bit of fill light. Two crops. Not much to choose between them on the crop of the kingfisher head apart from the higher level of fringing of the sigma (curiously the fringing gets worse as the f stop increases. A trick of the light perhaps, although I have another lens that does that - the Canon FD 400mm f4.5). The fine detail of the owl fluff is slightly but distinctly clearer with the D FA (less so actually when comparing the whole pics side by side in fastroom).
 
 
 
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.
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Forum: Lens Clubs
03-10-2024, 07:40 AM
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Good lens, mostly getting results similar to the DFA 150-450mm. The "superzoom" range does make it versatile.
U3A digital photography group trip to the Dingle, Llangefni, Anglesey. Red squirrel sanctuary - they're not shy, rather used to people and being given nuts etc. Ditto the robins. Pic 2 1:1 pixel peep crop.
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Forum: Lens Clubs
03-18-2024, 01:20 PM
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Some feeder pics. Much better light this time, and much better results.
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Forum: Lens Clubs
03-31-2024, 10:58 AM
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You get one bigma, then another one pops up.
The screw drive AF is the big difference with this one, noisy, clunking to and fro. But seems reasonably on it so far. It will take time to get a clear impression/verdict vs the HSM of the other one.
The avocets have been back at Burton Mere for a couple of weeks. I missed the ruddy shelducks, I was creeping around to get a better view through the branches when an egyptian goose took exception and chased them away.
Big ~ 1:1 crops on the avocets.
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Forum: Lens Clubs
04-06-2024, 12:25 PM
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According to this post on mflenses this was sold as a number of brands: Hanimex/Lentar/Prinz/Samigon/Telesar (with tripod mount) 500mm F8-16 M42 1970s
and on lens-db.com : Lentar 500mm f8...
aka Camron 500mm F/8 Mirror
aka Chinon 500mm F/8 Mirror
aka Hanimex 500mm F/8 Mirror
aka Kalimar 500mm F/8 Mirror
aka Listar 500mm F/8 Mirror
aka Prinz Miroflex 500mm F/8
aka Quantaray 500mm F/8 Mirror
aka Rexatar 500mm F/8 Mirror
aka Samigon 500mm F/8 Mirror
aka Soligor 500mm F/8 Mirror
aka Telesar 500mm F/8 Mirror
aka Vemar 500mm F/8 Mirror
The original manufacturer was probably Meibo (see the Lentar 250/5.6 Mirror).
And on m42.com it's described as a 500mm f8 mirror with built in neutral density filter.
The general experience is that these early mirrors aren't up to much...but we would be interested to see what you can do with it its certainly a handsome beast.
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Forum: Do-It-Yourself
04-07-2020, 10:39 AM
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Well the usable cell capacity (which is what we're talking about here really, not voltages per se) depends on two things: mainly the designed cell capacity as per specs; secondarily to what voltage it is charged to. 4.2V is totally standard, it is unusual actually to find a cell or charger that charges to a different voltage. In practice different chargers can result in slightly different end voltages. Some enthusiasts online are quite particular about what is a good end voltage, specifically many suggest it is better to go a bit less than 4.2v eg 4.1v to improve longevity and frown on chargers that tend to go over 4.2v slightly.
In any case as I point out in my write up the original pentax battery uses a 3rd party cell from panasonic. If you use the same replacement cell, new, that should avoid any issue you mention.
The usage life of my rebuilt battery is excellent btw, like a new one, I can once again grab the camera and assume I have life in the battery and usually be right.
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Forum: Pentax SLR Lens Discussion
04-03-2024, 10:46 AM
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Forum: Pentax SLR Lens Discussion
03-30-2024, 07:36 AM
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OK so here is a second look at the FA 80-320mm + hood, with a comparison between results at 320mm and at 260mm.
 
 
 
Definitely better, especially f8, f11 (which does tend to suggest I might have missed focus slightly the first time). There are some atmospheric effects visible (shimmering) in the 320mm f11 crop - conditions were not as good as yesterday. Not so much difference between 260mm and 320mm - definitely a bit sharper at f5.6.
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Forum: Pentax SLR Lens Discussion
03-28-2024, 10:52 AM
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OK so I snatched 15 mins this morning and took these test pics. Nice cool sunny conditions, The Great Orme is almost 2 miles away. I did notice a bit of shimmering in live view - atmospherics are always a potential issue with long distance. Bean bags on the car, 2 secs timer, MF in 10x live view.
I just took delivery of the 50-500mm EX yesterday.
Comments: I was surprised that the later sigma was if anything outperformed by the 1st gen one, but the detailed review here on PF does comment that that lens has an issue with distant focus at 500mm. The 135-400mm showed a bit better than I thought it would, and the pentax worse!
This is the view. You can compare the crops with similar images I took with the DFA 150-450mm and sigma EX DG 150-500mm here.
 
 
 
  
  
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Forum: Pentax SLR Lens Discussion
03-25-2024, 02:48 AM
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Being able to directly compare the 135-400mm with the 50-500mm I can remark the latter is by far the better lens at the long focal lengths. The 135-400mm is soft at 400mm f5.6. The conclusion I am already pencilling in for a review of the 135-400mm is that it is a good option/ higher specification alternative to the pentax F/FA 100-300mm/320mm lenses provided the price is right. I wouldn't pay more than 150-200US for one.
I'll post a quick test pic or two later.
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Forum: Lens Clubs
03-03-2024, 03:20 PM
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This was the last sigma x-500mm before abandoning pentax. These pics with OS on, camera VR off.
Versatility is the USP of this superzoom.
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Forum: Canon, Nikon, Sony, and Other Camera Brands
03-23-2024, 07:11 AM
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I would agree with luftluss that to match with M43 your best bet is a own-mount x-300mm. Particularly for an initial "have a go" enthusiasm. While there is extremely flexible mount adaptability on M43, you can mount up almost any lens with readily available cheap adapters, there is limited AF adaptability (olympus four thirds to M43; ?canon ef to M43...). If she gets serious then you can think a lot more about what camera+ lens.
Top tips: use a bean bag; use MF a lot and familiarise with focusing using magnification in the EVF/on the screen
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Forum: Pentax Camera and Field Accessories
03-19-2024, 02:23 AM
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Quite frankly, any decent monopod will do. A heavier duty one will flex less which is beneficial, with a monopod it's much more about how you use it. The big choice is what head. I use a largish ballhead, for me the flexibility of ballheads work well on a monopod. And you have the option of using it "gimbal" style: lay the ballhead at right angles into the slot. This works well when you need to point the lens well up or down. Although the weight well to one side can be a bit disconcerting.
I routinely have lenses like the DFA 150-450mm on a monopod. It's easy to carry with the lens over the shoulder, and I get better shots with the monopod taking the weight even if I am rather casual in my use of it. It's just a few seconds to take the lens off to use a beanbag or handhold.
Have a browse of the webpages out there discussing the different braced positions to stabilise yourself + monopod.
Addendum thats a Calumet carbon fibre monopod with a Novo CBH-46 ballhead. I also have a slik ballhead (I like the circular quick release plate design, but the ballhead is tending to be on the small size [c 40mm] for lenses like the DFA, and as another poster mentions, an arca plate fitting feels a bit more secure).
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Forum: Lens Clubs
03-04-2024, 12:57 PM
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Sigma DG OS HSM 50-500mm F4.5-6.3. This was the last sigma x-500mm before abandoning pentax. These pics with OS on, camera VR off, bean bag.
Results are competitive with DFA 150-450. The wagtail pics are 1:1 crops. The feeder pic was the best of a bad lot - sun went behind clouds, shutter speeds were too slow, all the shots suffered from movement blur and focus was difficult.
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Forum: Lens Clubs
03-03-2024, 12:50 PM
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Forum: Photographic Technique
02-21-2024, 02:28 AM
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Marginal to the point of irrelevance in most circumstances biz. Though when I was taking test pics with my 1000mm f8, I used two sandfilled bags: one for the lens to sit on and one on top!
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Forum: Photographic Technique
02-20-2024, 11:45 AM
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I make bean bags. For me they are an essential piece of kit, one lives permanently in the bag. The approx 6"/15cm dia x 2"/5cm height size is based on a commercial one and I find that's pretty fine for general purpose use - both for resting a camera + smaller lens on, or a long lens resting on its tripod mount (though often I have to make/use a larger or wider foot extension). I used to add both a grippy rubberised cloth on one side and a loop that would hook over the tripod mount foot so you could lift both lens and bean bag in one go. However I found I rarely used the latter so dispensed with it. Having a grippy side is however recommended.
Lots of things can be used as fillers but for me smooth roundish "nurdles" (raw plastic pellets, I get them for free from a local factory) are ideal.
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Forum: Pentax SLR Lens Discussion
02-19-2024, 12:08 PM
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Using manual focus telephotos is a continual test of technique and eyesight.
Your results are a not untypical outcome in poor light conditions IME, especially hand holding. Quite frankly, its hard to diagnose betwen low contrast due to light/lens/tc, softness due to a bit of shake etc especially at your slower shutter speeds of 1/350th (if you want to use the trad measure of 1/f for an adequate shutter speed then that would equate to min 1/600th with APSC sensor but personally I would try for 1/1000th), noise and missing critical focus.
As far as focus goes, you are rather more limited with a K20 because of the lack of good live view. Checking focus on the fly by examining the images on the screen is laborious. You would be much better off IMO with eg a cheap K30 (a good bargain choice because of the aperture solenoid issues).
To try to get the measure of what this lens and tc combo can do, then find opportunities where you can use a tripod or bean bag, remote shutter release and check the focus by review. As a general principle, any sort of support is going to improve things, I normally use a monopod in walkaround situations.
Practice and familiarity then is the way forward.
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Forum: Lens Clubs
09-26-2021, 11:49 AM
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I have acquired a minty example of the charmingly petite 300mm f5.6 mirror, found as numerous marques. Mine is an optomax.
I made a hood out of a gravy granules pot and a 67mm filter, deglassed.
This mirror is a very decent performer.
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Forum: Pentax Price Watch
01-26-2024, 07:39 AM
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Message from the seller:
"Hi there,The reason why this lens is not compatible for use on a K-1 OR K-1 II is due to the firmware of the lens being outdated.
We contacted sigma but it is now unable to be updated...." |
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Forum: Pentax KP
01-25-2024, 08:16 AM
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Many pentax models have the same jack plug as canons, and basically they all work, OEM/generic; penatx/canon.
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Forum: Lens Clubs
01-06-2024, 07:38 AM
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Bet you haven't seen one of these before.
The listing was collection only (always a bad move), the trick is then to offer to arrange the courier, seller was obliging.
Very dusty inside - only two elements so not enclosed at the mount end - and there is a chip/crack on the edge of the glass. Like the 500mm f4.5 and 1000mm f8's the M42 mount is attached with a screw sleeve so it can be removed and easily screwed into the camera. For the 1000mm I have been cogitating over diy-ing an adaptall mount* using a cannibalised deglassed 01F 2x tc, I think something similar should be doable with this lens.
*if any of you 500mm f4.5 or 1000mm owners want to discuss this msg me. |
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Forum: Do-It-Yourself
03-20-2020, 02:12 PM
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UPDATE: There are some other threads discussing batteries and battery capacities; FYI:
https://www.pentaxforums.com/forums/22-pentax-camera-field-accessories/42336...batteries.html
https://www.pentaxforums.com/forums/210-pentax-k-3-iii/427215-battery-question.html
https://www.pentaxforums.com/forums/6-pentax-dslr-discussion/422347-wasabi-b...rebuild-2.html
https://www.pentaxforums.com/forums/22-pentax-camera-field-accessories/34794...batteries.html
In particular photogem has been inspecting 3rd party batteries and comparing to original pentax batteries. He has observed:
- a lot of lower quality generic cells in the 3rd party batteries.
- the 3rd party batteries don't have a thermal sensor.
- or a balance charging BMS.
His review of a Wasabi battery is here. A significant risk with the 3rd party batteries is swelling. A significant advantage of rebuilding is maintaining quality.
Also PF member eccs19 (Mark Evers) has made this YouTube video:
You Tube
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src="https://www.youtube.com/embed/HAA7rQh06Bo?controls=1" allowfullscreen>
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As Li Ion batteries age the charge capacity steadily diminishes. As you can see in the first pic, the test result for one of my D-Li90's is now only 985mAh*, ~ half the original spec capacity of 1860mAh. It is a pretty old battery, the date code is 201009 ie this is over 10 years old so it's done pretty well.
While both pentax and third party batteries are readily available, the pentax battery is overpriced and you don't really know what the quality is of the third party ones. My own experience of buying and checking Li Ion battery cells is that outside of the main brand names like panasonic, samsung etc it's a bit of a lottery, the market is riddled with low quality or dodgy cells (especially ebay - for examples of really dodgy cells check out
You Tube
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src="https://www.youtube.com/embed/i96f9St_EH0?controls=1" allowfullscreen>
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- anything advertised with an OTT capacity rating ie above ~3500mAh can be assumed to be dodgy).
So the advantages of rebuilding are 1. cost and 2. quality control.
WARNING. This is what I did. You engage in something like this at your own risk. It is up to you to have sufficient diy and electrical know how. Don't disassemble a battery that hasn't been discharged. Take proper health and safety precautions.
TOOLS: modelling knife, soldering iron, plastic glue, gluegun. Multimeter useful for testing. Spot welder ideal for reassembly.
- The two halves of the case are glued/sealed together. I worked the tip of a knife blade along the join to separate. PIC 1
- The battery is a straightforward 2S/1P, 18500 cells (ie 18mm dia, 50mm length). There is a balance charging connection BC and a small control board CB. The MH12210 ID'ed these cells as panasonic. PIC 2.
- The cells are stuck to the base, ease out carefully. Note the polarity arrangement. I have already pulled off the spot welded link strip on the R ends. PIC 3.
- The control board is going to have to be soldered off to access the cell ends. PIC 4. The end solder points S are the ones. I intend to use the same connectors and (later) used some desolder wick to (partially) clear the connection points. PIC 5.
- These are the connectors. I used a dremel to remove them without bending/twisting. PIC 6.
- It is a good idea to use identical new cells. As well as varying capacity and quality, different cells are designed for different purposes eg high current for drills and tools. I think these are more oriented to capacity and durability. Panasonic MH12210 replacement cells are available from a number of suppliers, typical cost seems to be ~£6 each (UK). The supplier I enquired with (ecoluxshopdirect.co.uk) were out of stock but advised that the slightly cheaper Amsplus cells were essentially identical quality and spec so I went with that.
- A gluegun is standard for joining cells into a block PIC 7. The tags can be soldered back on but I have the right tool for this job, my newly commissioned MOT spot welder PIC 8.
If you are soldering, it is a bit more risky, in fact the seller of the cells I bought remarked that he had had a customer who had had problems soldering cells for a camera battery. My own tips: lightly sandpaper the surfaces, good quality flux, "hoof" profile soldering iron tip, Pb/Sn flux cored solder seems to work best. Also there is little room in the case for "lumpy" soldering, you will need to try to make the joint as flat as possible.
The rear tags are straightforward, then the front tags and control board are the ticklish part. I used bluetac (less secure, easier to microadjust position)/double sided sticky tape (more secure) to carefully position and hold the tags PIC 9 .
- Then resoldering the control board went smoothly, just a second or two contact with the iron and the old solder melted and the tag came though the slot.
- I now had a disconcerting moment when I couldn't get a voltage reading out of the battery. But the battery started charging fine (case left open to observe, check temperature by touch PIC 9) so it was just the control board registering that the cells were low and doing its job, switching the battery off.
- I suggest either a cyanoacrilate superglue, or plastic-weld solvent (I used the latter) to rejoin the case. Done (pic 10), battery works perfectly.
Overall I can say this is a straighforward, easy in fact, little diy exercise.
*except that later I realised that the Imax was faulty, consistently under-rating all the cells I tested with the discharge capacity function! The true capacity of the DLi90 was probably around 1500mAh - still significantly down on its rated 1800mAh.
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