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Forum: Pentax SLR Lens Discussion 09-16-2013, 03:13 PM  
F28 - FA31 Comparison (with photos)
Posted By JinDesu
Replies: 19
Views: 6,537
Well assuming you were shooting both from the same position, the first one is the 31mm due to larger subject size. Given the position of the balls in the background in relation to the kid, I think that supports my guess that the first one is the 31mm.

That being said, the first image is a bit warmer than the second. Looks more "daytime" than the second. The red cap is a bit more saturated in the first image. Shadows are about equal across both. Looking at the wall in the background, there appears to be more clarity in the first picture than the second. This is seen in the lighter rectangular section on the right side. The first image appears more contrasty than the second - I'm looking at the soccer ball.

That's my take on it. Now, looking at the overview - is one image THAT much more amazing in these two shots? I don't think so.
Forum: Lens Sample Photo Archive 12-22-2011, 10:07 PM  
Pentax DA 35mm f/2.4 AL samples
Posted By JinDesu
Replies: 103
Views: 53,696


F8, ISO 100, 5s
Forum: Lens Sample Photo Archive 09-02-2014, 05:08 AM  
Pentax SMC DA 18-135mm
Posted By JinDesu
Replies: 99
Views: 28,643
Some samples I shot:









Full size shot at 18mm and F4, resolves ridiculously well in the center on my k-3:
https://farm6.staticflickr.com/5574/15090000256_724feaaf02_o.jpg

Album here (with full size links):
https://www.flickr.com/photos/jindesu/sets/72157647123809512/
Forum: Pentax Lens Articles 09-17-2014, 01:10 PM  
Tamron 70-200 F2.8 vs Sigma 70-200 F2.8 EX DG HSM II - Battle of the older telephotos
Posted By JinDesu
Replies: 45
Views: 44,228
My friend recently told me that he was planning to sell his Sigma 70-200 F2.8 EX DG HSM II lens, and I saw an opportunity to borrow it to make a comparison review before he sold it off. And thus, a long and arduous task of trying to keep everything comparable begun.

The lenses:


Sigma 70-200 F2.8 EX DG HSM II - Link to PF's user reviews/specifications (Not to be confused with the most recent Sigma 70-200 iteration)

Tamron 70-200 F2.8 - Link to PF's user reviews/specifications

My full album of sample shots and comparisons. Includes full size image links shot on the k-3 (24MP)

Physical comparisons

The Tamron 70-200 F2.8 is surprisingly longer than the Sigma 70-200 F2.8 HSM II. I always thought the Tamron was the smallest of the bunch, compared to Sigma, Canon, Nikon, and even Pentax. That being said, the Tamron comes in at 200g less than the Sigma (and that weight can be seen in the girth).

The Sigma has the older crinkle finish. It felt quite solid, and the zoom and focus rings were smooth. The focus ring was especially nice to use in comparison to the Tamron, which has a AF/MF clutch by shifting the focus ring forwards and backwards. In addition, the manual focus of the Tamron had a little more friction and was not as enjoyable. The Tamron has a deeper/longer/more substantial hood, and I believe that it is a better hood. It certainly gives the lens a better look when compared side to side:



Both lenses have 77mm front elements that are non-rotating or extending. The lenses are (as typical of lenses in this class) internal focus and internal zoom. They both mounted nice and tight on my k-3, and I felt no wobble in any way on either lens. Both lenses have the classic positioning of zoom ring closer to the body, and focus ring closer to the front. This was changed in the most recent iteration of the Sigma, where the focus ring and the zoom rings swapped (I assume for faster autofocus).



On both lenses, the hoods are reversible and help with storing the lens. There aren't any discernible differences between the tripod feet. Both tripod feet rings have markings to indicate 90 degree positions, and the knobs are easy to use and tighten. I had no issues mounting either lens onto my tripod, and the feet stayed on nicely even when shifting the lens around.



I will comment that both Tamron and Sigma makes some really terribly difficult to use rear caps. Tamron's requires you to align the correct dot before turning. Sigma's turns the other way. Pentax's rear caps are significantly easier to use and I would go get myself a bunch of those just to replace the OEM ones from Sigma and Tamron.

Since the Tamron is my lens, I can comment on durability. I have used the lens since 2011 and it has continued to chug along. I had one scary spell when the lens had some issues autofocusing (I took it on a flight to Malaysia), and I couldn't solve the reason. After a month, the issue went away and the lens performance never changed. I've dinged it many times and the body is extremely resilient. It is super susceptible to dust, so there's quite a lot inside - but I never noticed any optical issues caused by the dust. So now that it is late 2014, the only problem I have is that the hood quick-connect mechanism is a bit loose and the lens hood does not stay on as tightly. I assume it's loosened on the hood itself and not on the lens hood-ring.

Autofocus performance:

Well, here is where people would assume that Tamron would lose out to the Sigma. From my experience with both lenses, I would disagree. I didn't do much of an AF test as I don't have the tools to make a consistent and repeatable test, so this section is just my opinion.

My first camera was the Pentax k-x, and I used my Tamron 70-200 on that camera until this year when I got a k-3. On the k-x, it was somewhat slow to focus - a person walking towards me would be a difficult shot to get. On everything else, the lens focused well (with a little adjustment).

Fast forward to now, and on my k-3 the Tamron is fantastic. I can track people walking towards me, birds flying towards and perpendicular to me, and I can lock onto a target very quick. It's noisier than the Sigma of course (microadjustments is quiet, but racking from near to far and vice versa is loud enough to disturb animals), but it is by no means slow. And on the k-3, it barely hunts. I've shot in bright and dim conditions, and the Tamron is a new beast with the k-3.

The Sigma is no slouch on the k-3 either. Everyone knows of how the Sigma HSM is better than Pentax's SDM (or at least, that's the note I gather from this forum) - and I will admit, my Sigma 50 F1.4 HSM was faster focusing and had less hunting than my DA*55 F1.4. The Sigma was quick to focus and very silent. I sometimes wouldn't know if it actually performed the microadjustment, because there was no sound. When it hunts, it hunts very quickly (the image just goes in and out of focus so fast). It is fast enough for tracking a person walking towards me, and the limitation is mostly the k-3.

So for both lenses, I would say the AF is mostly equal in speed and consistency, with the edge going to the Sigma for quietness.
Bokeh!All my photos were edited for brightness and white balance only - I tried to get the white balance similar so that it doesn't bias anyone when dealing with sharpness. No sharpening was added to the images - but I did increase the clarity a little (on par with what I do for all my photos). All shots were processed in Lightroom 5.0.
So I am going to start with bokeh first, because the lens resolution section is long and arduous, and anyone who finishes through it is going to be too tired to look at anything else.

My impression after having looked at both lenses is that the Tamron has a marginally better bokeh overall, but the two of them create very smooth backgrounds that it doesn't really make a difference which lens to use. Their effect on specular highlights is not unpleasing, and at 200mm they make the background melt into a blur. This may be surprising as the Tamron is highly touted for bokeh, but the Sigma isn't often mentioned. I know that my DA*55 F1.4 had better bokeh than my Sigma 50 F1.4, but in the 70-200 - the bokeh is lovely and I don't really have any issues with it.

Tamron:




Sigma:





Full size link: https://farm4.staticflickr.com/3865/15264094812_cb54ae826f_o.jpg

Please see the album linked in the beginning for more bokeh samples.

Flare performance:

I tried to get the flare performance test to be the same framing for both lenses, but the Sigma (I think) changes the frame a little because it is slightly shorter than the Tamron. As such, the flare performance test is shorter and less comprehensive compared to the rest.

My opinion from the test is that the Tamron performs remarkably better on flare. In all scenarios, the Tamron either had less flare, or less distracting flare. I attribute it partly to the hood and to the better coatings perhaps.

Tamron (first) and Sigma (second) at 70mm F2.8:



Tamron (first) and Sigma (second) at 200mm F2.8:



Please see the album linked in the beginning for more flare samples.

Image Quality

And now we come to the section that most people (or at least, in my head) care about. Now to preface this section, I did this just for fun and I do not have all the tools to make perfect comparisons between the lenses. For one, the Tamron focuses closer than the Sigma, and for another, the Sigma has a tendency to frame a little more at the same camera distance. So I did my best to keep everything as similar as possible, and I know I made one or two focus mistakes in the whole set. Also, I didn't bother doing corner/edge performance because I don't have a subject flat enough to do that.

When doing this test, while there are some differences between the lenses wide open, they pretty much evened up by F4 at any aperture/focal length. By F5.6, they were pretty much equal and I would say both lenses are extremely sharp. I know that my Tamron 70-200 is sharp enough to resolve pores on half body portraits, so it's definitely sharp enough for my use. For a professional environment, I find both lenses sharp enough to get the job done (unless you want to compare it to a prime, but that's a different animal).

At F2.8 and their sharpest focal lengths, I would say that both lenses resolve as much detail as my DA*55 F1.4 when stopped down to F2. They are definitely not lacking in detail.

I will break down the comparisons into three parts. In each part, I will show the test image and a link to the full size image for perusal, because I can't link full size images to PF. The test image is a side by side comparison of center 100% crops. The full images are on my flickr in the album as linked at the beginning of this post. Each image has a full size link in the comments, so I am presenting everything up to scrutiny (including how dusty my area is).

Close focus (minimum FD for Sigma, close to minimum FD for Tamron)
At 70mm-135mm, I find the Tamron to have an edge over the Sigma at F2.8. They even out around F5.6. The difference is noticeable, but the Sigma isn't bad. At 200mm, the Tamron's performance drops significantly, introducing a lot of bloom. I attribute bloom to lack of contrast, and the hood not being size for 200mm (otherwise it'll vignette). As far as sharpness goes, the Sigma will win this round, but they both equalize around F4, and become very sharp at F5.6.

This test is also where I think I got the Tamron 200mm F2.8 focus slightly off, which can make a big difference. On the other hand, at minimum focal distance - the Tamron was always a little weak in my experience.


https://farm4.staticflickr.com/3836/15264095392_a9ef9014a1_o.jpg


https://farm6.staticflickr.com/5586/15077915917_623b71c6ec_o.jpg


https://farm6.staticflickr.com/5572/15264486505_9f400e0816_o.jpg


https://farm4.staticflickr.com/3887/15077915667_d99a46151c_o.jpg

Medium focus distance (About 12', or good for portraits)
At the medium focus distance, the IQ of the lenses followed a similar pattern to the close focus shots. From 70-135mm at F2.8, the Tamron is sharper at the center than the Sigma. At 70mm, the Sigma gets an edge at F4, but then they both tie up at F5.6. From 100-135mm, the Sigma ties up at F4. At 200mm F2.8, the Tamron and Sigma look about equal in performance. The Sigma shows a bit more contrast, but I don't think it's resolving more. By F4, they are both very sharp. I would say that at 200mm, the Sigma has an edge overall from F2.8-F8, while the Tamron wins out similarly at 135mm.


https://farm6.staticflickr.com/5565/15077782140_b11be2a045_o.jpg


https://farm4.staticflickr.com/3866/15077917077_a665f5fe4f_o.jpg


https://farm6.staticflickr.com/5558/15264096262_9b889b5ea0_o.jpg


https://farm4.staticflickr.com/3852/15261389501_dea802a07f_o.jpg

Semi-far focus distance (About 22-24', or where I take pictures of animals and stuff)
In the semi-far distance test, I found the Tamron to start outperforming the Sigma wide open at all focal lengths. i skipped the 100mm focal length in this test, but I could see a clear difference between the Tamron and the Sigma at F2.8 in the 70mm, 135mm, and 200mm range. The Sigma ties up around F4, but I would give the general edge to the Tamron at 70mm and 200mm, and the Sigma wins a little at 135mm.


https://farm4.staticflickr.com/3901/15241474896_8cefb225d7_o.jpg


https://farm6.staticflickr.com/5553/15264487095_2c24aaa0b2_o.jpg


https://farm4.staticflickr.com/3909/15264486785_f05a34106e_o.jpg

Infinity focus distance (About infinity, or where I take pictures of far away things)
I didn't take this test. I didn't really have a location where I could set up and do a consistent test in this range. I apologize for my laziness, but I think the above tests give a good indication of what the lenses can do. In addition, I've shot infinity shots with my Tamron before, and I find that the atmospheric aberrations and the heat effects do way more to the image than the lens will. Also, people don't tend to take infinity shots with these lenses at F2.8, so it may be a moot point anyways.

REMEMBER, EACH SAMPLE SHOT IS FOLLOWED BY A FULL SIZE LINK. THE SAMPLE SHOTS WERE SCALED DOWN TO BE POSTED ON PF.

Chromatic Aberrations/Coma/Vignetting
I must apologize that I do not have a way to test for CA/coma easily. Neither lens showed much CA in my testing, with the exception of LoCA in the OOF areas. As far as vignetting goes, I have not been bothered by either lens. Cycling between the photos in my Flickr album will give an example of how the vignetting shows up, but I didn't have a large flat white wall to do the test with.

Conclusion (i.e. which one is better?)
Well, I don't know. The Tamron is priced at $769 at B&H right now, and used is typically $450-500. The Sigma isn't even on B&H anymore for Pentax, and was replaced with a newer APO EX DG version that is also not available in stores for Pentax. The newer version is said to be sharper than the HSM II, and the retail price was around $1199 when I last saw it. The HSM II version was probably that price before it got replaced, and I see it used at around $800 now. So IQ/value wise, the Tamron definitely wins. Its sharpness practically the same (wins some, loses some) to the Sigma, but at $300-500 less it is a bargain. It's also the cheapest of the 70-200s, and from everything I've read on this forum, it and the Sigma are amongst the top performing.

I've used the Tamron for 3 years now and I always enjoy using it. It has a nice solid body, it has fast AF on my k-3, it hasn't let me down yet, and Tamron gives a nice 6 year warranty (I think Sigma is 2 years for non-EX, and 4 years for EX lenses). The Sigma's good points are the silent autofocus and the smoother focus/zoom rings. If I had the money to spend, I would go with the Sigma for the silent autofocus. Or even for the newer version, which is supposed to be sharper. If I were on a budget, or I didn't care about silent autofocus, the Tamron would be a sure buy for me.

Of course, there's also the DA*50-135, DA*60-250, the Tokina 80-200 F2.8 ATX, the Pentax FA*80-200 F2.8, and the Sigma 50-150 F2.8 EX DG HSM. There is a Pentax official review of the FA*, the newer Sigma (APO EX DG), and the Tamron at this link, but it doesn't provide much info on the image quality. To me, I think all these lenses will have similar sharpness and the overall difference is the features and handling.

Let me know if there are any questions and I will try to answer them to the best of my ability. I am limited by the fact that I had returned the Sigma to my friend for him to sell.

Also for convenience, so you don't need to scroll all the way back up, the link to the album is: https://www.flickr.com/photos/jindesu/sets/72157647685646442/
Forum: Troubleshooting and Beginner Help 03-15-2013, 05:54 AM  
Why is it better to have more focus points?
Posted By JinDesu
Replies: 31
Views: 6,919
There's two items to consider - focus points and focus point size. More focus points means the focus point size must be smaller.

Let's start with the number of focus points - the reason for this is focus tracking. See examples below:




The first image is a Olympus E-3 with 11 points. The second is the 1D Mk3 with 40 something points. See the density difference? If you are tracking a bird with one point on the E-3, and it moves into one of the empty spaces in the AF grid, your E-3 will stop tracking it. It might not even be able to start tracking again when the bird reaches the next AF point. This is partly the processing requirements (to recognize the same subject). The 1D Mk3 doesn't have as much "empty space". Thus - it will track better.

This is most applicable to tracking - users of single point AF won't notice the difference between these two (except for focus point size issues). Without a large number of focus points, Predictive AF is not going to be reliable.

As for AF point size - the k-5 is notorious for having "large" focus points. A large focus sensor can be problematic because the single sensor can "see" multiple objects and will select one of those objects to focus onto - for example, if you are taking picture of a bird who is somewhat far away, the focus sensor might focus on the bird.. or something it also sees in the foreground (branches) or background (branches). It doesn't know what YOU want to focus on, so it'll just guess. Smaller focus points means you have finer control.

Smaller focus points have it's own issues, because if you don't have a good density of them, you have to use focus and recompose. For example, in the E-3 image - if those points were small, then if I wanted to take a picture of someone's face where the eyes are not at the center of the frame, there is no focus point I could select to focus on the eyes. I would have to focus and recompose.

In summary - quantity of focus points matter most when dealing with tracking. When dealing with single point autofocus, quantity of focus points doesn't really matter. Focus point size must also be taken into consideration.
Forum: Lens Clubs 12-15-2014, 12:03 PM  
DA Limited Zoom Club
Posted By JinDesu
Replies: 1,029
Views: 231,692
The DA 20-40 is great in bad weather. I adore using it. It does have a little issue with highlight bokeh circles - could be dust on my copy though.







Forum: Pentax SLR Lens Discussion 10-12-2012, 08:30 AM  
Sigma - 70-200/2.8 EX DG OS APO HSM IF **** VS ****70-200/2.8 EX DG II APO Macro HSM
Posted By JinDesu
Replies: 13
Views: 5,536
I've heard it is fantastically sharper than the II. Even sharper than the Tamron 70-200, which competes with the top line 70-200s.

As far as settling for the DA 200 prime - the DA*200 prime is going to be sharper regardless, but maybe at such a degree that it doesn't really matter to you. What does matter, however, is the use. A 70-200 can double as a portrait lens, as well as a short sports or birding lens. A DA*200 is going to find very restricted use in portrait shooting.
Forum: Pentax News and Rumors 02-22-2018, 08:08 AM  
The official presentation (Ricoh) of the Pentax Mark II
Posted By JinDesu
Replies: 331
Views: 40,658
Man, it must suck to be Pentax sometimes. They bring out the k-5 and nothing for a while, and people say they are doomed. Then they bring out the k-5ii with some cool stuff while they test the waters with their lower end cameras in the k-30/k-50 range and people say they are doomed. Then they bring out the k-3 which was quite an upgrade from the k-5 in several ways, and then people were saying that Pentax is doomed because they stay in the APSC market. Then they brought out the k-3ii with minor upgrades while focusing on their internal development and people continued saying that Pentax is doomed.

Then they brought out the k-1 and people were saying that Pentax is doomed for bringing out a full frame so late and giving up on the APSC market. And now they bring out the k-1ii, basically in the same fashion that they've done for the k-5, k-3, and technically everything in between, and it's a black mark on Pentax for not innovating.
Forum: Pentax SLR Lens Discussion 06-10-2013, 05:26 AM  
Help me get starburst effect with 15mm limited
Posted By JinDesu
Replies: 18
Views: 4,798
Shoot F11+. My DA 21 will get starbursts under the right conditions at F8. Making the aperture smaller will increase the size of the starbursts. Only lights that are in focus will generate starbursts. While F11 on a DA 15 has a deep depth of field, it still helps to aim your focus for the regions where you want the starburst to pop out. Bright conditions can make it hard to starburst - you want an exposure where your light source is brighter than it's surroundings. Exposure bracketing can help to shoot multiple exposures and see which looks best.
Forum: Pentax K-3 & K-3 II 10-10-2013, 10:04 AM  
why I won't buy a k3 (Warning: Satire Thread)
Posted By JinDesu
Replies: 102,988
Views: 4,826,397
This thread is depressing.
Forum: Repairs and Warranty Service 06-30-2017, 07:02 AM  
It's dead Jim! Need input on my K3 paperweight.
Posted By JinDesu
Replies: 16
Views: 2,648
I second this test. I freaked out once thinking my k-3 was dead when I left the door open and didn't pay attention. It looks practically non-functioning in that mode.
Forum: Pentax KP 01-26-2017, 03:40 PM  
Thanks Ricoh
Posted By JinDesu
Replies: 28
Views: 2,994
Thank you Ricoh, for keeping Pentax going ever since Pentax was supposed to be doomed like 6 years ago. Or longer, I forget.
Forum: Pentax DSLR Discussion 01-06-2017, 12:41 PM  
Thieves broke in my Van Last night.....Stole a new K-1 , other camera and bag !
Posted By JinDesu
Replies: 218
Views: 25,067
Fantastic news, that GPS paid itself off!
Forum: Pentax DSLR Discussion 01-01-2017, 08:34 AM  
Thieves broke in my Van Last night.....Stole a new K-1 , other camera and bag !
Posted By JinDesu
Replies: 218
Views: 25,067
holy cow, fantastic that you have two methods of tracking in that - hope those thieves get busted!
Forum: Photographic Technique 12-13-2016, 02:19 PM  
Thoughts on ISO
Posted By JinDesu
Replies: 71
Views: 5,896
Image noise is the sensor (of film, or music recorder, or whatever) lacking enough distinct signal to differentiate from general ambient signal - in the case of a image sensor that ambient signal is the general electrical field around the sensor. Where the incoming signal is not distinct, the local ambient signal may trigger the sensor pixels to register as red, green, or blue, and create the noise. Just as if you had a microphone and you hear static from the ambient electrical fields around the signal delivery circuits within.

ISO determines how much electrical amplification is applied to the sensor. A higher ISO is a higher electrical amplification to improve sensitivity to the lower input signal. Higher electrical amplification has the side effect of having a strong electrical field around that sensor, and therefore has a better chance of triggering the sensor with noise instead of the incoming signal.

Darker parts of a scene will have noise as the incoming signal from those areas may not be strong enough to differentiate from the electrical ambient signal. If you shoot a sunlit scene with a dark shadow even at ISO 100, the electrical ambient signal on the sensor may be stronger than the few photons you receive from that region in the shadow.

Similarly, out of focus regions may generate more noise because the incoming signal is seen as indistinct by the sensor.
Forum: Pentax DSLR Discussion 09-08-2016, 06:22 AM  
Ricoh quiet about K3 2 Successor
Posted By JinDesu
Replies: 147
Views: 17,377
Man, and here I'm stuck with my obsolete k-3. Guess I shouldn't bother taking photos ever until I get a new camera...
Forum: Pentax K-1 & K-1 II 09-10-2016, 11:57 AM  
Too much noise on K-1
Posted By JinDesu
Replies: 50
Views: 9,553
Gaweidert, the two images you shot with the k-5IIs and presented here have bright sources of light in them. Despite the camera selecting ISO 3200, the brighter overall frame and the especially bright areas will have significantly less noise than if you took a less lit image at ISO 3200 - even with the same camera. Noise is random electrical signal triggering the sensor's individual pixels. At high ISO, the sensitivity is amplified and thus the noise has a higher chance of triggering the pixel. Having a subject that is bright will cause the sensor to clearly capture that subject even if you are at high sensitivity - as the bright subject is a much stronger signal than the random noise. Therefore the first shot with the bright lamp and the second shot with the fire is going to seem less noisy at ISO 3200 than if those two sources of light weren't there.

In your k-1 shot, there is no bright sources of light. It's evenly dark and in that case, noise will be most prevalent. You must compare equally lit and equally colourful images to get a properly determination of noise levels between two cameras.

I have neither camera so I am not saying that your k-1 is definitely better or equal to the k-5IIs, although it should be as they share the same base sensor (just different size), I am just explaining that linking two images of significantly different light levels and subjects is not a good way to judge noise.
Forum: Pentax SLR Lens Discussion 08-11-2016, 05:46 PM  
Pentax/Ricoh "new" lenses
Posted By JinDesu
Replies: 30
Views: 3,143
Pentax goes and makes the 20-40, the 18-50RE, the 55-300RE, and Pentaxians complain about how they don't make fast glass, or pro glass, or how the 20-40 is too slow etc.

Pentax goes and makes the 24-70 and the 70-200 and Pentaxians complain aabout how they don't make small glass anymore and how everything is too big and too heavy.

...dafuq.
Forum: Pentax K-1 & K-1 II 02-19-2016, 01:22 PM  
Pentax K-1 "Thank you" Thread
Posted By JinDesu
Replies: 104
Views: 10,876
Very well done, Pentax & Ricoh!
Forum: Pentax SLR Lens Discussion 02-19-2016, 08:09 AM  
Pentax 20-40 best uses
Posted By JinDesu
Replies: 27
Views: 3,445
I use it for almost everything except wildlife lol..

On my k-3 it's good enough for indoor shots, and since it's weathersealed and silent, I just leave it on the k-3. But if I were to say it's suited for something, it's suited for street photography due to it's small size, silent and reasonably quick AF, and the slow aperture is mitigated by having outside daylight.

Just to throw some shots out there:

DA 20-40 F2.8-4 Ltd Lens Sample #14 by Jing Soong, on Flickr

DA 20-40 F2.8-4 Ltd Lens Sample #13 by Jing Soong, on Flickr

DA 20-40 F2.8-4 Ltd Lens Sample #11 by Jing Soong, on Flickr
Forum: Pentax DSLR Discussion 02-18-2016, 08:43 AM  
I intentionally tossed my KS-2 in mud on a rainy day
Posted By JinDesu
Replies: 16
Views: 2,659
Between this thread and your knife on lens thread, I am cringing everytime I see your name pop up on the new threads list.
Forum: Pentax SLR Lens Discussion 10-08-2015, 01:17 PM  
Are all copies of SMC Pentax-FA* 28-70mm F2.8 AL soft at 70 mm f 2.8?
Posted By JinDesu
Replies: 22
Views: 3,016
Yep, many zoom lenses have different focusing characteristics throughout their range. My Tamron 70-200 backfocuses at 70mm, is neutral near 135mm, and front focuses at 200mm. I set it to correct for front focusing because the backfocusing at the short range is not that pronounced.

Your solution may be to test the focusing characteristics and see if adjusting it for slight front focus may help at 70mm and may not affect 24-69mm - or you could keep it in mind and just aim further behind your targets when at 70mm.
Forum: Lens Sample Photo Archive 12-22-2011, 10:19 PM  
Tamron 70-200mm SP AF f/2.8 Di LD IF samples
Posted By JinDesu
Replies: 149
Views: 50,759
I shall counter with another hawk


F4, 200mm, ISO 200, 1/400s


F4, 170mm, ISO 320, 1/500s


F4, 200mm, ISO 640, 1/600s


F4, 140mm, ISO 200, 1/640s


F5.6, 70mm, ISO 100, 1/80s
Forum: Pentax News and Rumors 09-25-2015, 07:03 AM  
DFA 24-70mm to be launched soon
Posted By JinDesu
Replies: 323
Views: 43,883
It's not like Pentax recently made a DFA 150-450 and is also bringing out a DFA*70-200, both of which are Pentax lenses and Pentax designs. And it's not like the 150-450 is pretty universally praised.

Such a horrendous tragedy.
Forum: Lens Sample Photo Archive 08-25-2015, 08:30 AM  
Tamron 70-200mm SP AF f/2.8 Di LD IF samples
Posted By JinDesu
Replies: 149
Views: 50,759
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