Here lately wherever you can find them. There seems to have been a run on them since September. Some of the more popular ones are on backorder at most stores.
Tried to edit the message but was too late ….. wondering too …. if there were any ‘recommended lenses’ you may have in mind? such as ‘doublers’?
My 35mm days are so long ago …. I remember for instance having a zoom lens (actually all the lenses) for my old Minolta SRT 101 that had a scale on the barrel that would roughly show me the depth of field depending on the aperture setting I choose. Seems the lenses (the kit lenses Sigma 28-90 and 70-300) have no such scale. Looking at the booklet though has a portion for ‘viewing DOF preview’. Haven’t experimented with it yet but tends to tell me things work very differently today than 20 years ago.
Sooooo excited about my new camera – what a lucky guy.
Value wise it is hard to beat the Canon 50 f 1.8. Everyone seems to think it is very sharp and with the 1.6 x50mm it gives you a pretty good portrait lens. It along with a 90 or 100 mm macro on my list of goodies.
Buz, about the depth of field, probably we have to rethink about what we considered the DOF in analogue photography and in digital photography. There is a nice explanation about DOF on <http://www.photozone.de/3Technology/demos/depth2.htm>
In this article it reads:
Thus, one way of indicating the quality of a lens is by the smallest dot it can form, or its Βminimum circle of confusion.Β <
As DSLR cameras become more and more accepted, a lot of optics are recalculated and improved. There is a maximum that film can reproduce and optical engineers were able to build optics that outperformed film, but didnot as it was useless. Now we see new lenses come to the market with a higher resolution than ever before as digital seems to be able to reproduce more than film ever could.
If "digital lenses" produce higher resolution images, the minimal circle of confusion will be smaller too, so we will have to reconsider our "standard" DOF as we knew until now.
I understand (for the most part) and will review the link you provided. Seems though that DOF should be DOF which to me in my ‘old’ 35mm days meant: that horizontal area in front of the camera that would be in focus (the nearest and furthest objects) and this DOF was dictated by the aperture (the higher the f stop # (smaller actual aperture opening) equalled a greater DOF.
"As DSLR cameras become more and more accepted, a lot of optics are recalculated and improved. There is a maximum that film can reproduce and optical engineers were able to build optics that outperformed film, but didnot as it was useless. Now we see new lenses come to the market with a higher resolution than ever before as digital seems to be able to reproduce more than film ever could".
Len
Oh my a parting of the ways.
The total resolution of a system is based not only the lens but also the target (film or CCD/CMOS chip). At 55 lpmm digital chips do match or slightly exceed the resolution of colour print film. Because of the size of the chips in dSLR you can now expect to get about the same resolution as you can from a good APS system. Due to the nature of over all system even a vastly superior lens will only improve the over all resolution of digital a small amount. Once the chips sizes of dSLR equal to size of 35 mm film then you will have cameras capable of deliver slightly better resolution than 35 mm print film. Of course to be truly compatible digital chips will have to be able to match the resolution of extremely high resolution film which can reach 700 lpmm.
Originally the size of a circle of confusion was selected to give a crisp image of an 8×10 as viewed at 12" I believe at this distance the COC is 1/100". Therefore anything that appears larger than this circle of confusion is considered out of focus.
The 1/100" of an inch is base on the expected resolving power of a human eye. The 8×10 at 12" is based on the field of view of the human eye excluding peripheral vision.
Grant, we are both right. As usual. My purely theoretical statement about a smaller circle of confusion was based on the status quo of other factors like film resolution and "film size". As far as I remember you are right in your next posting about how we came to defining what is supposed to be sharp.
I’m not sure if this should be a separate thread or maybe even in a different forum (DP?).
It relates to lenses and digital photography in general …… and in a way it relates to PSE as well …..
So there’s been some good discussion on lenses, dof, coc, etc ….. where do lens filters fit in digital photography – i.e. skylight, uv, polarizer, etc. Should one use these filters as in the pre-digital era or is PSE something that would negate the need for the various filters?
I just remember how much I grew to rely on my polarizer for various ‘bright’ situations and the dramatic affect it had on the image.
Buz, I don’t think we should start a separate thread on DOF this way. It will be too technical and hardly anyone will be interested to go deep into this "problem" as it has hardly any consequences.
Filters might be different, especially polarizers and soft focus attachments.
My opinion: I hardly ever use polarizers as they tend to exaggerate the blues of the sky way too much. The only times I use this filter is when copying oil paintings to remove unwanted reflections and when I have to photograph gardens , This filter is the best way to make a lawn look as green as it should be as it dampens the reflections on the leaves.
A good soft focus filter like the Zeiss or Heliopan Softar can add a romantic feel to an image that is extremely difficult to be imitated in a digital way.
I suspect there are many opinion so here is mine. Filter are by their nature subtractors not adder so when you use them you subtract so why limit your intake you can adjust this in Elements (Keeping it on topic π There are a few exceptions Polar, IR and neutral density being three that I can think of. While you may be able to come close to simulating this in Elements ( again on topic) you really can’t duplicate them. Two other you mentioned Daylight and UV may also be of help but I would think their main purpose is to protect the end of you camera lens from bumps and dirt and scratches.
I don’t think you can get a zoom with Depth Of Field marked on the lens barrel anymore. The DOF changes with the focal length and focusing distances. Just found some old lens manuals in a box. For my Nikkor zooms, there is a chart showing the approximate DOF of different focal lengths (not continuous but at most popular focal lengths of fixed lenses, like 24, 28, 35, ….) at varying focusing distances.
The closest thing to what you are after may be those old Kodak Retina cameras with interchangeable (front element only) lenses made by Kodak or Schneider-Kreuznach. I borrowed one form my brother inlaw and was amazed to discover a pair of red prongs mechanically centered on the aperture ring. They closed in as the aperture gets wider (smaller numbers) and wider apart as the lens was stopped down. However, they did not move with changes in focusing distance. It’s a piece of cake to place the infinity mark on the distance ring at the one end of the red prong for hyperfocal distance setting. You may be still able to check out these cameras out in a well stocked used camera store.
I have looked at (played with) the DOF preview button and have yet to see it’s ‘meaning’ – just sems to turn the view finder dark – not sure how to interpret it?
IMHO discussions of digital camera technology is On Topic, but others may differ.
As to filters, the need for filters for BW (reds and yellows) are not necessary with digital, since those kinds of effects are done with post processing. Polarizers are useful for reducing glare, and an IR filter effect can’t really be duplicated in post processing (faked, but not duplicated). Soft focus can be done with a gaussian blur on a separate layer with partial opacity for control.
As far as lenses go, I think the Canon 28-135 USM with Image Stabalization is a good choice for either the Rebel and the 10D. Sigma also has some good wide angle lenses that would be a good choice.
buz: I have looked at (played with) the DOF preview button and have
yet to see it’s ‘meaning’ – just sems to turn the view finder dark – not sure how to interpret it?
Yes, it DOES get dark, doesn’t it? Darker than your average SLR. But the PURPOSE is to show the scene with the lens ‘stopped down’ to your chosen aperture, so you can more accurately see the depth of field. Unfortunately, at very small apertures it becomes so dark in the finder that it’s difficult to tell. It used to be that virtually all lenses had distance and depth-of-field aperture markings on them, so you could get a rough idea without using the finder. But with the popularity of zooms and auto-focus, many newer lenses don’t have this info engraved on them.
To SEE the effect, choose a BRIGHTLY LIT scene with a subject say 10 feet away and other objects a few feet in front and behind. Focus on the 10 ft. mark. The objects in front and behind should appear out of focus. Now choose a more ‘closed’ aperture, f8 say, hit the depth of field button and observe the difference in sharpness of the objects front and rear. Now choose f16 (if you can still see in the finder).
John, re the dark viewfinder when using the DOF preview: I was never able to use it on a 35 mm camera in my younger days, and I certainly can’t do so with my eyesight deteriorating. An(other) unused button on my camera… π Chuck
While I do not use my DOF preview button for most broad scenic situation I do use it for close up work. While my eyes are fading I do know where bright sport are for shooting flowers.
My question regarding where was answered and I see the ‘which lenses’ part of the question is producing some very good reading as well as things to ponder.
Regarding "where" to purchase… I’ve purchased from B&H and Canoga Camera, and like them both. Canoga seems to offer a little more personalized service, but that’s not a big deal. Both have similar pricing.
Someone mentioned the Canon EF 28-135 USM-IS lens. I have this lens (using it on a 10D). It’s a nice upper- middle of road lens, both in terms of focal length and image quality. Given the 1.6x conversion factor, the resulting focal lengths on the Rebel are 44.8-216. It doesn’t perform like a wide angle, but offers a good standard length to medium telephoto. The Image Stabilization (IS) is a nice feature allowing you to hand hold 1 to 2 stops slower that normal.
At f4-5.6, it’s not a terribly fast lens, but it seems to be a good balance of price, size and versatility. Anything faster in that zoom range will be much larger and cost over $1,000. The Canon CMOS sensor is pretty low noise at ISO’s of 400 and above so that offers a reasonable compromise for the lens speed too.
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