chetan_dighe

<p>Another one - just the head shot</p><div></div>

<p>Cheeta from Botswana</p><div></div>

<p>I have used extension tubes, reversal rings and closeup filter attachments for macro work. I have also used a macro lens once (50/4), and the results were similar to reversal ring based experiments.<br>

All of them give good results, but closeup filter attachments allow autofocus. For manual focus, extension tubes reduce the light, so it works only with fast lenses (50/1.4, for instance). However, since these are basic (single element) convex lenses, they (may) create cromatic aberration. I have tried using an achromatic doublet attached to a UV filter, and mounted it on the lens, with a slightly better color control.<br>

Extension tubes also reduce the light, and I normally use them to reduce the closest focussing distance of my 300/4 (normal min focussing distance 18 feet).<br>

Lenses mounted on Reversal Rings also work fine, but give vignetting at smaller apertures. Works ok if you are only interested in the central circle.<br>

More than just the lenses / attachments, I suppose we also need a very fine manual focusing mechanism, such as rails / bellows / etc. We also need a sturdy tripod, as handheld body movement can really kill an otherwise great shot. The DOF is really very shallow (a few milimeters) at real close distances (2 to 3 inches).</p>

<p>I use my K10D mostly with all my manual focus lenses. And I rarely use anything other than M mode and Green button. Works great. At times, I do have to change exposure by one stop, but thats not very often.<br>

Please consider K10D (and manual focus lenses) as a very good choice you have made. Don't regret ;-)</p>

<p>In the manual focus range - try m42 85/1.8 - great portrait lens for K10D. Only shortcoming - bokeh !!! Wish it came with more blades in the aperture.<br>

Cheers.</p>

<p>Try primes - 50/1.4, 85/1.8, 105/2.8, 135/2.5 or 2.8 or 3.5<br>

With K10D, the focal length will be 1.6 times the full frame focal length. This means 50, 85 and 105 will be ideal. Make sure whatever lens you use, it is fast. Wide open aperture will give you best background blurs. Besides, also look for more number of aperture blades. That will again make the aperture round, and background blur smooth.<br>

For budget concerns, look for screw mount manual lenses. They are great value for money.<br>

Cheers.</p>

I hope you have set the "aperture ring" to "permited" (custom menu, last page, second last option).

I have been using manual focus lenses on K10D body with almost no problems. When I need quality, I also use tripod and timer to avoid camera shake. At times I do use a Hartmann mask for longer focal lengths. Despite all these, I do admit my manual focus is not as accurate as autofocus.

This (allow aperture ring) is the second last option on the last page in custom menu.

Set it to permitted.

BTW, does anybody know why pentax gave this option? I mean, what would they gain by "not permitting" it? Couldn't they have simply dropped the option from the menu and set the default to permitted? My autofocus lens works well with the "permitted" option. Beats me.

Sorry for being late to respond ..

Tamron lenses basically come without a mount, incomplete in a way, and then you buy the mount to make it complete. So, that way, if you have more than one bodies, all you do is buy the basic lens, and one mount per body. Simple.

I have kept my older manual lenses, 50/1.4, 24/2.8, 28-105/3.5-4.5, 28-200/3.8-6.3, and use them more frequently than the kit lens. Not that it is bad, but others are better. Plus, the rebate you get on not buying the kit lens is not much, so just take it with the body. Later, upgrade to better lenses.

M42 adaptors with flanges will work like your K mount lenses. However they will not reach infinity focus because they move the lens away from the mount.

 

????????????????????????????????????

 

I am thinking of going for an M42 lens with "flange" adapter for my K10D. I am perfectly ok with manual focus. Question is - does it work on k10D? I am interested in infinity focus, cant live without it.

 

I have other K mount lenses, all manual, and they work with the custom setting "aperture ring" permitted. Focussing is, off course, manual. Wont the M42 manual lenses work the same way?

a GOOD "overall" zoom lens ...

=================================

I have tried 28-200, 28-70, 28-105, 70-210.

 

For their respective ranges, all lenses performed very well at both ends, except for the 28-200. Basically, (I think) if the zoom ratio (max / min) goes beyond 4, you lose on quality. Probably, my 28-200 would perform best actually at, say, 35-140 range. Don't know for sure, will have to try. But how to compare? Tough.

 

I would prefer splitting the entire range (whatever you are interested in) into at least two lenses, 28-80 and 75-300, rather than one 28-300, even though the latter is cheaper and more convenient, only because the former would give me better quality. Of course, one can also add some exotic 11-22 and 170-500, but I am not so RICH ...

 

If you just want one lens, general purpose, IMHO 28-105 is the unbeatable choice. Of course, brands do have their own quality dimensions, but mostly all of them essentially use the same optical calculations, even though the glass and mechanical quality differs.

 

Please correct me if I am wrong.

 

Cheers.

Try doing this at night -

 

Set multiple exposures to 2.

Put your camera on a tripod, aim outside your window on faraway street lights, focus sharp, and click.

Without moving the camera, defocus a little bit, till the street lights become bigger blobs, and click.

 

The merged images will show both - the blobs with the sharp lights in their center.

 

You will also notice that the lights in the center of the frame have the sharp spots in the center of the blobs, and those towards the edge have the sharp spots towards the center of the frame. Spherecal abberation in the lens? I don't know, but would like somebody to throw some light (no pun intended !!!).

 

If all this is confusing due to my poor ability to write, please try it out for yourself at night. ;-)

 

Cheers.

Thanks guys.

 

I noticed the same stuff, and was wondering if this is a problem at all, or is it supposed to be that way.

 

It is the NR that was delaying writing my night shots to the card. I also tried without NR, but then, the noise tells me that it is better to let the camera do its job its own way.

 

BTW, I am trying to hook my K10D to my telescope for night shots, and I usually have the whole night to wait, so no hurry ...

 

Cheers.

although if you look at some of the crops you can see some demosaicing artifacts)."

==============================================================

Sorry, but what is "demosaicing"?

Sorry for being late on the entry.

 

I don't have first hand experience of D200 / D80, but considering these are Nikon products, they must be pretty good, if not the best in class.

 

I own K10D. My reason for K10D is primarily compatibility with my existing set of lenses - 50/1.4, 24/2.8, 28-105/3.5-5.6, 28-200/3.5-5.6, all k-mounts, MF. I personally have no issues with manual focus and manual exposure control (in fact, I kind of love it. Isn't that real photography?), but having tested autofocus on K10D's kit lens, would like to make my future lens collection expansion on autos.

 

Kit lens of k10d (18-55) is not all that great, but not all that bad either. After all, it is just a kit lens. Instead, I wanted 16-45/f4, but unfortunately, it was not available at that moment, and the dealer was not willing to sell me just the body.

 

As for comparison, I suppose you can only put K10D and D80 on the same pedestal, as D200 would be in a different class because of full-frame sensor. Besides that, I guess all other differences, such as weight and feel and control positions etc are superficial, and are just a matter of getting used to. The menu of K10D is fine, once you figure out what all you can set / change, and their philosophy behind structuring it that way.

 

On the price front, K10D is a great surprize, especially if you compare the features (in-body shake reduction, dust removal, weather seals, two RAW formats, ...). Other brands in the same / comparable price ranges have half / one generation older models (Canon 350D, for instance), or smaller sensors (Olympus, for instance). Again, none of the brands / products are bad, but then, "better" is always "better". The best of the deal is the value for money, and on that count, no one can beat K10D. For (lucky) me, a new collection of my existign lenses today would cost me more than half the price of the K10D body, and everybody knows the resale value of old lenses. Point is, ...

 

Cheers.

 

All opinions are personal, and as my dear Richard Bach puts it, all that is written above could be wrong ;-)

Hi Vignesh,

Hope the problem is solved.

With the new K10D (I don't know if this is also available on *ist DS), you get TAv mode. With the custom setting of Aperture Ring "permitted", this I found to be the best mode for manual lenses.

Regards,

Chetan.

Hello,

 

I bought my K10D last saturday (26th May 2007) after a long deliberation, primarily to ensure it takes all my manual pentax lenses.

 

AND IT DOES.

 

I am talking about K mount lenses without A setting on the aperture ring, since I have four of them.

 

First of all, you need to go into Custom Menu and set Aperture Ring setting (somewhere towards the end on page 6!!!) to "permitted". The default is otherwise. I don't understand why the default is "not permitted", since the kit lens that comes with the camera by default, and all other Auto focus lenses work equally well with that option set to "permitted". With this option set to "permitted", and Shake Reduction set to on (on the back side, right side lower corner next to the lcd panel), whenever you restart the camera, you are asked to select the focal length of the lens. (Probably, that is the reason the default is off. It is too much of a nuisance to the Auto world !!!).

 

Anyway, that out of the way, you need to set the front side selector to MF (and not to AF.C or AF.S).

 

Then the mode dial works in M, Av, Tv, TAv, Green, P, B, etc. The aperture ring actually works, as I was able to take a lot of trafic trails last night with tripod mouted camera using 24 MM manual lens set to f/16 set for 30 seconds. The picture blurred drastically when I opened to f/2.8 for that duration.

 

Basically, the aperture ring on the manual lenses (without A settings) works. In the shop where I bought this, I also saw how effortlessly lenses with A setting took to this body.

 

I need to check what happens in the AF.S or AF.C mode with a manual lens. A week is too short to learn it all. All the best to me.

 

Cheers,

 

Chetan.

Hi,

 

First post needs relevant introduction - chetan from mumbai, been using slr for past 15 years, always learning (sophisticated way of justifying your mistakes ;-) ).

 

I own a few pentax k mount lenses (all manual focus), so was waiting for a long time for pentax to come up with a good (price and specs) DSLR. Now with K10D, I don't need to wait any longer.

 

Today, when I went to pick up the k10d body, I tried all my MF lenses (pentax 50/1.4 and 24/2.8, ricoh 28-105/2.5-4.x, tamron 28-200/3.5-5.6, all giving great results on my pentax and cosina bodies), none could focus correctly. Body showed error F. The image formed thru the viewfinder was always hazy, whatever we did. We tried another body (K100D), but had the same result. Both bodies worked properly with the kit lenses.

 

Question : Assuming that pentax claim of any K mount lens made in the past 30 years fitting these bodies is correct, are there any specific settings to allow MF lenses to focus correctly? I remember when I bought the tamron 28-200 two years ago, I had to try a few adaptall mounts before I could get the infinity focus right.

 

Thanks in advance, -- Chetan

Hello all,

 

Sorry for entering the thread so late, seems like it has died.

 

I have gone thru all the responses, but frankly, I am still confused by what is written here.

 

For one, I believe that f number is the ratio of aperture diameter / focal length. For instance, a 50 mm aperture with a 100 mm focal length would make it f/2. If we want a 600 mm focal length in f/2, we would need an actual opening of 300 mm. I know it would not be practical to carry around a lense so huge, but theoretically, I suppose this explains the point.

 

This (constant aperture) would ensure that the angle the focusing beam makes would be the same at all focal lengths. Not very sure, but I guess this 'angle' is what matters in deciding the depth of field, spherical aberration caused by paraxial rays, etc. Correct me if I am wrong.

 

Now, about constant aperture for the entire zoom range.

 

Over and above what is covered so far in this thread, I believe if we can somehow maintain the same beam angle at all focal lengths, we would achieve "constant aperture".

 

One way to achieve this would be, to move a fixed diameter hole back and forth in the tube, depending on the focal length (probably in a non-linear way if the optical combination so behaves), so as to maintain the curtailed angle of the light beam constant. This way, we would have a constant aperture.

 

Those who have played around with optics would know that this will lead to barrel or pincushion distortion (which can again be corrected by some more optical elements), as basic optics textbooks explain, but it would achieve our "constant aperture" objective.

 

I don't know if this approach is actually used by the manufacturers, whether the resulting image quality would be acceptable, would "professionals" pay more for "constant aperture" if the image distortion is high, would this still be called "professional" lense, and so on.

 

Any comments on this one?

 

Regards,

 

Chetan.